The Collaborative International Dictionary of English v.0.48:

Lax \Lax\, n.
   A looseness; diarrhea.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lax \Lax\ (l[a^]ks), a. [Compar. Laxer (l[a^]ks"[~e]r);
   superl. Laxest.] [L. laxus Cf. Laches, Languish,
   Lease, v. t., Leash.]
   1. Not tense, firm, or rigid; loose; slack; as, a lax
      bandage; lax fiber.
      [1913 Webster]

            The flesh of that sort of fish being lax and spongy.
                                                  --Ray.
      [1913 Webster]

   2. Not strict or stringent; not exact; loose; weak; vague;
      equivocal.
      [1913 Webster]

            The discipline was lax.               --Macaulay.
      [1913 Webster]

            Society at that epoch was lenient, if not lax, in
            matters of the passions.              --J. A.
                                                  Symonds.
      [1913 Webster]

            The word "[ae]ternus" itself is sometimes of a lax
            signification.                        --Jortin.
      [1913 Webster]

   3. Having a looseness of the bowels; diarrheal.
      [1913 Webster]

   Syn: Loose; slack; vague; unconfined; unrestrained;
        dissolute; licentious.
        [1913 Webster]

WordNet (r) 3.0 (2006):

lax
    adj 1: lacking in rigor or strictness; "such lax and slipshod
           ways are no longer acceptable"; "lax in attending
           classes"; "slack in maintaining discipline" [syn: lax,
           slack]
    2: pronounced with muscles of the tongue and jaw relatively
       relaxed (e.g., the vowel sound in `bet') [ant: tense]
    3: lacking in strength or firmness or resilience; "a lax rope";
       "a limp handshake" [ant: tense]
    4: emptying easily or excessively; "loose bowels" [syn: lax,
       loose]

Moby Thesaurus II by Grady Ward, 1.0:

316 Moby Thesaurus words for "lax":
   Micawberish, Paphian, abandoned, accented, accepting, admissive,
   aleatoric, aleatory, allowing, alveolar, amorphous, apical,
   apico-alveolar, apico-dental, approximate, approximative,
   articulated, assimilated, back, backward, bagging, baggy, barytone,
   behindhand, bilabial, blobby, blurred, blurry, bone-lazy, broad,
   broad-minded, cacuminal, cadging, careless, central, cerebral,
   chambering, chance, chancy, chaotic, checked, clement, close,
   compassionate, confused, consenting, consonant, consonantal,
   continuant, culpably negligent, dallying, dangling, delaying,
   delinquent, dental, derelict, dilatory, dillydallying, disordered,
   disregardful, dissimilated, do-nothing, doless, dorsal, dronish,
   drony, drooping, ease, ease off, easy, easygoing, ergophobic,
   faineant, flabby, flaccid, flapping, flat, flimsy, floppy, foggy,
   foot-dragging, forbearant, forbearing, forgetful, forgiving,
   freethinking, front, fuzzy, general, gentle, glide, glossal,
   glottal, go-go, good-for-nothing, guttural, hanging, hard, hazy,
   heavy, high, hit-or-miss, humane, ill-defined, immoderate,
   impotent, imprecise, inaccurate, inadvertent, inattentive,
   inchoate, incoherent, incontinent, incorrect, indecisive,
   indefinable, indefinite, indeterminable, indeterminate,
   indifferent, indistinct, indolent, indulgent, inexact, intemperate,
   intonated, irrepressible, labial, labiodental, labiovelar,
   lackadaisical, laggard, lagging, laissez-faire, lateral,
   latitudinarian, lazy, lenient, liberal, libertarian, libertine,
   licentious, light, limp, lingering, lingual, liquid, loitering,
   loose, loose-moraled, loosen, low, merciful, mid, mild, moderate,
   monophthongal, muted, narrow, nasal, nasalized, neglectful,
   neglecting, negligent, nonaggressive, noninterfering,
   nonprohibitive, nonrestrictive, nonspecific, oblivious, obscure,
   occlusive, of easy virtue, of loose morals, off-guard, open,
   open-minded, orderless, out of control, out of hand, out of line,
   out of plumb, out of square, out of true, overindulgent,
   overly permissive, overpermissive, oxytone, palatal, palatalized,
   parasitic, patient, permissive, permitting, pharyngeal,
   pharyngealized, phonemic, phonetic, phonic, pitch, pitched,
   posttonic, procrastinating, procrastinative, procrastinatory,
   promiscuous, rampant, random, regardless, reinless, relax, relaxed,
   remiss, retroflex, rickety, riotous, rounded, rubbery, scamping,
   scrounging, semivowel, shadowed forth, shadowy, shaky, shapeless,
   shiftless, shuffling, skimping, slack, slacken, slighting,
   slipshod, sloppy, slothful, slow, sluggish, slurring, soft, sonant,
   sponging, stochastic, stopped, streaming, stressed, strong,
   suffering, surd, sweeping, syllabic, tender, tense, thick, throaty,
   tolerant, tolerating, tonal, tonic, twangy, unaccented, unbigoted,
   unbridled, unchecked, uncircumspect, unclear, uncoerced,
   uncompelled, unconstrained, uncontrolled, uncurbed, undefined,
   undestined, undetermined, unenterprising, unfactual, unforced,
   ungoverned, unguarded, uninhibited, unmastered, unmeasured,
   unmindful, unmuzzled, unplain, unprecise, unprohibitive, unreined,
   unrepressed, unreserved, unrestrained, unrestrictive, unrigorous,
   unrounded, unruly, unspecified, unstressed, unsubdued,
   unsuppressed, untighten, unwary, unwatchful, vague, veiled, velar,
   vocalic, vocoid, voiced, voiceless, vowel, vowellike, wanton,
   wayward, weak, whorish, wide, wild, work-shy



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

LAX

   LAnguage eXample.

   A toy language used to illustrate compiler design.

   ["Compiler Construction", W.M. Waite et al, Springer 1984].

   (1994-12-07)