The Collaborative International Dictionary of English v.0.48:

Habit \Hab"it\ (h[a^]b"[i^]t) n. [OE. habit, abit, F. habit, fr.
   L. habitus state, appearance, dress, fr. habere to have, be
   in a condition; prob. akin to E. have. See Have, and cf.
   Able, Binnacle, Debt, Due, Exhibit, Malady.]
   1. The usual condition or state of a person or thing, either
      natural or acquired, regarded as something had, possessed,
      and firmly retained; as, a religious habit; his habit is
      morose; elms have a spreading habit; esp., physical
      temperament or constitution; as, a full habit of body.
      [1913 Webster]

   2. (Biol.) The general appearance and manner of life of a
      living organism. Specifically, the tendency of a plant or
      animal to grow in a certain way; as, the deciduous habit
      of certain trees.
      [1913 Webster +PJC]

   3. Fixed or established custom; ordinary course of conduct;
      practice; usage; hence, prominently, the involuntary
      tendency or aptitude to perform certain actions which is
      acquired by their frequent repetition; as, habit is second
      nature; also, peculiar ways of acting; characteristic
      forms of behavior.
      [1913 Webster]

            A man of very shy, retired habits.    --W. Irving.
      [1913 Webster]

   4. Outward appearance; attire; dress; hence, a garment; esp.,
      a closely fitting garment or dress worn by ladies; as, a
      riding habit.
      [1913 Webster]

            Costly thy habit as thy purse can buy. --Shak.
      [1913 Webster]

            There are, among the statues, several of Venus, in
            different habits.                     --Addison.

   5. Hence: The distinctive clothing worn commonly by nuns or
      monks; as, in the late 1900's many orders of nuns
      discarded their habits and began to dress as ordinary lay
      women.
      [PJC]

   Syn: Practice; mode; manner; way; custom; fashion.

   Usage: Habit, Custom. Habit is a disposition or tendency
          leading us to do easily, naturally, and with growing
          certainty, what we do often; custom is external, being
          habitual use or the frequent repetition of the same
          act. The two operate reciprocally on each other. The
          custom of giving produces a habit of liberality;
          habits of devotion promote the custom of going to
          church. Custom also supposes an act of the will,
          selecting given modes of procedure; habit is a law of
          our being, a kind of "second nature" which grows up
          within us.
          [1913 Webster]

                How use doth breed a habit in a man! --Shak.
          [1913 Webster]

                He who reigns . . . upheld by old repute,
                Consent, or custom                --Milton.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Habit \Hab"it\ (h[a^]b"[i^]t), v. t. [imp. & p. p. Habited; p.
   pr. & vb. n. Habiting.] [OE. habiten to dwell, F. habiter,
   fr. L. habitare to have frequently, to dwell, intens. fr.
   habere to have. See Habit, n.]
   1. To inhabit. [Obs.]
      [1913 Webster]

            In thilke places as they [birds] habiten. --Rom. of
                                                  R.
      [1913 Webster]

   2. To dress; to clothe; to array.
      [1913 Webster]

            They habited themselves like those rural deities.
                                                  --Dryden.
      [1913 Webster]

   3. To accustom; to habituate. [Obs.]           --Chapman.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

168 Moby Thesaurus words for "habit":
   a habit, accouter, acquired tolerance, acute alcoholism,
   addictedness, addiction, alcoholism,
   amphetamine withdrawal symptoms, apparel, array, attire, attitude,
   automatism, bad habit, barbiturate addiction, barbiturism,
   bedizenment, bent, bib and tucker, body-build, brand, caparison,
   cast, chain smoking, character, characteristic, characteristics,
   chronic alcoholism, clothes, clothing, cocainism, complexion,
   composition, compulsion, constituents, constitution, convention,
   costume, crash, crasis, craving, creature of habit, custom,
   dependence, dharma, diathesis, dipsomania, disguise, disposition,
   drapery, dress, dressing, drug addiction, drug culture,
   drug dependence, duds, equip, ethos, fashion, fatigues, feathers,
   fiber, fig, fit, fit out, force of habit, frame, frame of mind,
   frock, garb, garments, gear, genius, grain, guise, habiliment,
   habiliments, habit pattern, habituation, habitude, hue, humor,
   humors, idiosyncrasy, ilk, inclination, investiture, investment,
   kind, linen, livery, makeup, manner, mannerism, masquerade,
   minauderie, mode, mold, nature, nicotine addiction, outfit,
   pattern, peculiar trait, peculiarity, penchant,
   physical dependence, physique, policy, practice, praxis,
   predisposition, proclivity, propensity, property,
   psychological dependence, quality, quirk, rags, raiment, regalia,
   rig, rig out, rig up, robes, routine, rule, second nature,
   somatotype, sort, spirit, sportswear, stamp, stereotype,
   stereotyped behavior, streak, stripe, style, suchness, suit,
   system, temper, temperament, tendency, tenor, threads, togs,
   toilette, tolerance, tone, trademark, trick, trick of behavior,
   trim, turn out, type, uniform, usage, use, vein, vestment,
   vestments, vesture, way, wear, wearing apparel,
   withdrawal sickness, withdrawal symptoms, wont



The Devil's Dictionary (1881-1906):

HABIT, n.  A shackle for the free.