The Collaborative International Dictionary of English v.0.48:

False \False\, a. [Compar. Falser; superl. Falsest.] [L.
   falsus, p. p. of fallere to deceive; cf. OF. faus, fals, F.
   faux, and AS. fals fraud. See Fail, Fall.]
   1. Uttering falsehood; unveracious; given to deceit;
      dishnest; as, a false witness.
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   2. Not faithful or loyal, as to obligations, allegiance,
      vows, etc.; untrue; treacherous; perfidious; as, a false
      friend, lover, or subject; false to promises.
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            I to myself was false, ere thou to me. --Milton.
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   3. Not according with truth or reality; not true; fitted or
      likely to deceive or disappoint; as, a false statement.
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   4. Not genuine or real; assumed or designed to deceive;
      counterfeit; hypocritical; as, false tears; false modesty;
      false colors; false jewelry.
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            False face must hide what the false heart doth know.
                                                  --Shak.
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   5. Not well founded; not firm or trustworthy; erroneous; as,
      a false claim; a false conclusion; a false construction in
      grammar.
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            Whose false foundation waves have swept away.
                                                  --Spenser.
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   6. Not essential or permanent, as parts of a structure which
      are temporary or supplemental.
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   7. (Mus.) Not in tune.
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   False arch (Arch.), a member having the appearance of an
      arch, though not of arch construction.

   False attic, an architectural erection above the main
      cornice, concealing a roof, but not having windows or
      inclosing rooms.

   False bearing, any bearing which is not directly upon a
      vertical support; thus, the weight carried by a corbel has
      a false bearing.

   False cadence, an imperfect or interrupted cadence.

   False conception (Med.), an abnormal conception in which a
      mole, or misshapen fleshy mass, is produced instead of a
      properly organized fetus.

   False croup (Med.), a spasmodic affection of the larynx
      attended with the symptoms of membranous croup, but
      unassociated with the deposit of a fibrinous membrane.

   False door or False window (Arch.), the representation of
      a door or window, inserted to complete a series of doors
      or windows or to give symmetry.

   False fire, a combustible carried by vessels of war,
      chiefly for signaling, but sometimes burned for the
      purpose of deceiving an enemy; also, a light on shore for
      decoying a vessel to destruction.

   False galena. See Blende.

   False imprisonment (Law), the arrest and imprisonment of a
      person without warrant or cause, or contrary to law; or
      the unlawful detaining of a person in custody.

   False keel (Naut.), the timber below the main keel, used to
      serve both as a protection and to increase the shio's
      lateral resistance.

   False key, a picklock.

   False leg. (Zool.) See Proleg.

   False membrane (Med.), the fibrinous deposit formed in
      croup and diphtheria, and resembling in appearance an
      animal membrane.

   False papers (Naut.), documents carried by a ship giving
      false representations respecting her cargo, destination,
      etc., for the purpose of deceiving.

   False passage (Surg.), an unnatural passage leading off
      from a natural canal, such as the urethra, and produced
      usually by the unskillful introduction of instruments.

   False personation (Law), the intentional false assumption
      of the name and personality of another.

   False pretenses (Law), false representations concerning
      past or present facts and events, for the purpose of
      defrauding another.

   False rail (Naut.), a thin piece of timber placed on top of
      the head rail to strengthen it.

   False relation (Mus.), a progression in harmony, in which a
      certain note in a chord appears in the next chord prefixed
      by a flat or sharp.

   False return (Law), an untrue return made to a process by
      the officer to whom it was delivered for execution.

   False ribs (Anat.), the asternal rebs, of which there are
      five pairs in man.

   False roof (Arch.), the space between the upper ceiling and
      the roof. --Oxford Gloss.

   False token, a false mark or other symbol, used for
      fraudulent purposes.

   False scorpion (Zool.), any arachnid of the genus
      Chelifer. See Book scorpion.

   False tack (Naut.), a coming up into the wind and filling
      away again on the same tack.

   False vampire (Zool.), the Vampyrus spectrum of South
      America, formerly erroneously supposed to have
      blood-sucking habits; -- called also vampire, and ghost
      vampire. The genuine blood-sucking bats belong to the
      genera Desmodus and Diphylla. See Vampire.

   False window. (Arch.) See False door, above.

   False wing. (Zool.) See Alula, and Bastard wing, under
      Bastard.

   False works (Civil Engin.), construction works to
      facilitate the erection of the main work, as scaffolding,
      bridge centering, etc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

False \False\, v. t. [L. falsare to falsify, fr. falsus: cf. F.
   fausser. See False, a.]
   1. To report falsely; to falsify. [Obs.] --Chaucer.
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   2. To betray; to falsify. [Obs.]
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            [He] hath his truthe falsed in this wise. --Chaucer.
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   3. To mislead by want of truth; to deceive. [Obs.]
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            In his falsed fancy.                  --Spenser.
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   4. To feign; to pretend to make. [Obs.] "And falsed oft his
      blows." --Spenser.
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The Collaborative International Dictionary of English v.0.48:

False \False\, adv.
   Not truly; not honestly; falsely. "You play me false."
   --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

false
    adv 1: in a disloyal and faithless manner; "he behaved
           treacherously"; "his wife played him false" [syn:
           faithlessly, traitorously, treacherously,
           treasonably, false]
    adj 1: not in accordance with the fact or reality or actuality;
           "gave false testimony under oath"; "false tales of
           bravery" [ant: true]
    2: arising from error; "a false assumption"; "a mistaken view of
       the situation" [syn: false, mistaken]
    3: erroneous and usually accidental; "a false start"; "a false
       alarm"
    4: deliberately deceptive; "false pretenses"
    5: inappropriate to reality or facts; "delusive faith in a
       wonder drug"; "delusive expectations"; "false hopes" [syn:
       delusive, false]
    6: not genuine or real; being an imitation of the genuine
       article; "it isn't fake anything; it's real synthetic fur";
       "faux pearls"; "false teeth"; "decorated with imitation palm
       leaves"; "a purse of simulated alligator hide" [syn: fake,
       false, faux, imitation, simulated]
    7: designed to deceive; "a suitcase with a false bottom"
    8: inaccurate in pitch; "a false (or sour) note"; "her singing
       was off key" [syn: false, off-key, sour]
    9: adopted in order to deceive; "an assumed name"; "an assumed
       cheerfulness"; "a fictitious address"; "fictive sympathy"; "a
       pretended interest"; "a put-on childish voice"; "sham
       modesty" [syn: assumed, false, fictitious, fictive,
       pretended, put on, sham]
    10: (used especially of persons) not dependable in devotion or
        affection; unfaithful; "a false friend"; "when lovers prove
        untrue" [syn: false, untrue]

Moby Thesaurus II by Grady Ward, 1.0:

217 Moby Thesaurus words for "false":
   Barmecidal, Barmecide, Machiavellian, Tartuffian, Tartuffish,
   aberrant, abroad, adrift, affected, airy, all abroad, all off,
   all wrong, ambidextrous, amiss, apostate, apparent, apparitional,
   artful, artificial, askew, astray, at fault, autistic, awry,
   backsliding, baseborn, bastard, beguiling, beside the mark, bogus,
   brummagem, calculating, canting, catchy, chimeric, chiseling,
   collusive, concocted, contrary to fact, corrupt, counterfeit,
   counterfeited, covinous, crafty, crooked, cunning, deceitful,
   deceiving, deceptive, defective, deluding, delusional, delusionary,
   delusive, delusory, dereistic, derelict, deviant, deviational,
   deviative, devious, disaffected, dishonest, disloyal, distorted,
   double, double-dealing, double-faced, double-minded,
   double-tongued, doublehearted, dreamlike, dreamy, dubious, dummy,
   duplicitous, errant, erring, erroneous, ersatz, fabricated,
   factitious, faithless, fake, faked, fallacious, false-principled,
   falsehearted, fantastic, faultful, faulty, feigned, fickle,
   fictitious, finagling, fishy, flawed, forged, fraudulent, furtive,
   goody, goody-goody, guileful, hallucinatory, heretical, heterodox,
   holier-than-thou, hollow, hypocritical, illegitimate, illogical,
   illusional, illusionary, illusive, illusory, imaginary, imitation,
   imprecise, in error, inaccurate, inconstant, incorrect, indirect,
   inexact, insidious, insincere, invalid, lying, made-up,
   manufactured, mealymouthed, mendacious, meretricious, misbegotten,
   miscreated, misleading, mistaken, mock, not right, not true,
   not true to, of bad faith, off, off the track, ostensible, out,
   peccant, perfidious, perverse, perverted, phantasmagoric,
   phantasmal, phantom, pharisaic, phony, pietistic, pinchbeck, pious,
   pseudo, questionable, recreant, renegade, sanctified,
   sanctimonious, scheming, seeming, self-contradictory,
   self-deceptive, self-deluding, self-righteous, sham, sharp, shifty,
   simulated, slippery, sneaky, snide, sniveling, specious, spectral,
   spurious, straying, substitute, supposititious, surreptitious,
   synthetic, traitorous, treacherous, trickish, tricksy, tricky,
   trothless, truthless, two-faced, unactual, unctuous, underhand,
   underhanded, unfactual, unfaithful, unfounded, unloyal, unnatural,
   unorthodox, unproved, unreal, unsound, unsteadfast, unsubstantial,
   untrue, untrustworthy, untruthful, visionary, wide, wily, wrong



The Free On-line Dictionary of Computing (30 December 2018):

FALSE

   A small, compiled extensible language with lambda
   abstractions by W. van Oortmerssen.

   For Amiga (ftp://ftp.cso.uiuc.edu/pub/amiga/fish/ff885).