The Collaborative International Dictionary of English v.0.48:

Inhibit \In*hib"it\, v. t. [imp. & p. p. Inhibited; p. pr. &
   vb. n. Inhibiting.] [L. inhibitus, p. p. of inhibere; pref.
   in- in + habere to have, hold. See Habit.]
   [1913 Webster]
   1. To check; to hold back; to restrain; to hinder.
      [1913 Webster]

            Their motions also are excited or inhibited . . . by
            the objects without them.             --Bentley.
      [1913 Webster]

   2. To forbid; to prohibit; to interdict.
      [1913 Webster]

            All men were inhibited, by proclamation, at the
            dissolution, so much as to mention a Parliament.
                                                  --Clarendon.
      [1913 Webster]

            Burial may not be inhibited or denied to any one.
                                                  --Ayliffe.
      [1913 Webster]

   3. (Chem., Biochem.) To cause the rate of (a chemical or
      biochemical reaction) to proceed slower, or to halt; as,
      vitamin C inhibits oxidation; penicillins inhibit
      bacterial cell wall synthesis.
      [PJC]

   4. To restrain (a behavior) by a mechanism involving
      conscious or unconscious motivations.
      [PJC]

WordNet (r) 3.0 (2006):

inhibit
    v 1: to put down by force or authority; "suppress a nascent
         uprising"; "stamp down on littering"; "conquer one's
         desires" [syn: suppress, stamp down, inhibit,
         subdue, conquer, curb]
    2: limit the range or extent of; "Contact between the young was
       inhibited by strict social customs"
    3: limit, block, or decrease the action or function of; "inhibit
       the action of the enzyme"; "inhibit the rate of a chemical
       reaction"
    4: control and refrain from showing; of emotions, desires,
       impulses, or behavior [syn: inhibit, bottle up,
       suppress]

Moby Thesaurus II by Grady Ward, 1.0:

134 Moby Thesaurus words for "inhibit":
   arrest, avert, ban, bar, bit, bottle up, box up, bridle, cage,
   check, cloister, confine, constrain, contain, control, cool,
   cool off, coop, coop in, coop up, cork up, countercheck, crib,
   curb, curtail, dam up, damp, dampen, debar, decelerate, delay,
   deny, detain, disallow, discourage, dompt, embargo, encage,
   enclose, enjoin, exclude, exclude from, fence in, forbid,
   frustrate, govern, guard, hem in, hinder, hold, hold at bay,
   hold back, hold down, hold fast, hold in, hold in check,
   hold in custody, hold in leash, hold in restraint, hold up, immure,
   impede, impound, intercept, interdict, interfere, interfere with,
   intermeddle, interrupt, intervene, keep, keep back, keep from,
   keep in, keep in check, keep in custody, keep in detention,
   keep under, keep under control, lay under restraint, lock in,
   maintain, meddle, mew, mew up, obstruct, oppose, outlaw, pen,
   pen up, pound, preclude, preserve, prevent, prohibit, proscribe,
   pull, pull in, rail in, refuse, rein, rein in, reject, repress,
   resist, restrain, restrict, retain, retard, retrench, rule out,
   save, save up, say no to, scotch, seal up, set back, shackle,
   shut in, shut out, shut up, slacken, slow down, smother, snub,
   stifle, stop, straiten, sublimate, suppress, taboo, wall in, ward,
   withhold