The Collaborative International Dictionary of English v.0.48:

Instinct \In*stinct"\, a. [L. instinctus, p. p. of instinguere
   to instigate, incite; cf. instigare to instigate. Cf.
   Instigate, Distinguish.]
   Urged or stimulated from within; naturally moved or impelled;
   imbued; animated; alive; quick; as, birds instinct with life.
   [1913 Webster]

         The chariot of paternal deity . . .
         Itself instinct with spirit, but convoyed
         By four cherubic shapes.                 --Milton.
   [1913 Webster]

         A noble performance, instinct with sound principle.
                                                  --Brougham.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Instinct \In"stinct\ ([i^]n"st[i^][ng]kt), n. [L. instinctus
   instigation, impulse, fr. instinguere to instigate: cf. F.
   instinct. See Instinct, a.]
   [1913 Webster]
   1. Natural inward impulse; unconscious, involuntary, or
      unreasoning prompting to any mode of action, whether
      bodily, or mental, without a distinct apprehension of the
      end or object to be accomplished.
      [1913 Webster]

            An instinct is a propensity prior to experience, and
            independent of instructions.          --Paley.
      [1913 Webster]

            An instinct is a blind tendency to some mode of
            action, independent of any consideration, on the
            part of the agent, of the end to which the action
            leads.                                --Whately.
      [1913 Webster]

            An instinct is an agent which performs blindly and
            ignorantly a work of intelligence and knowledge.
                                                  --Sir W.
                                                  Hamilton.
      [1913 Webster]

            By a divine instinct, men's minds mistrust
            Ensuing dangers.                      --Shak.
      [1913 Webster]

   2. (Zool.) Specif., the natural, unreasoning, impulse by
      which an animal is guided to the performance of any
      action, without thought of improvement in the method.
      [1913 Webster]

            The resemblance between what originally was a habit,
            and an instinct becomes so close as not to be
            distinguished.                        --Darwin.
      [1913 Webster]

   3. A natural aptitude or knack; a predilection; as, an
      instinct for order; to be modest by instinct.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Instinct \In*stinct"\ ([i^]n*st[i^][ng]kt"), v. t.
   To impress, as an animating power, or instinct. [Obs.]
   --Bentley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

instinct
    adj 1: (followed by `with')deeply filled or permeated; "imbued
           with the spirit of the Reformation"; "words instinct with
           love"; "it is replete with misery" [syn: instinct(p),
           replete(p)]
    n 1: inborn pattern of behavior often responsive to specific
         stimuli; "the spawning instinct in salmon"; "altruistic
         instincts in social animals" [syn: instinct, inherent
         aptitude]

Moby Thesaurus II by Grady Ward, 1.0:

120 Moby Thesaurus words for "instinct":
   a thing for, ability, affinity, aptitude, aptness,
   archetypal pattern, archetype, automatic response,
   automatic writing, automatism, bent, bias, blind impulse,
   brain wave, brainstorm, bump, caliber, capability, capacity, cast,
   collective unconscious, compulsiveness, conatus, conditioning,
   conduciveness, delight, diathesis, disposition, dower, dowry,
   drive, eagerness, echolalia, echopraxia, empathy, endowment,
   equipment, faculty, fancy, feel, feeling, feeling for, flair,
   flash, fleeting impulse, forte, genius, gift, gut response, id,
   impulse, inborn proclivity, inclination, inspiration,
   instinctiveness, intuition, involuntariness, involuntary impulse,
   knack, leaning, liability, libido, liking, long suit, makings,
   metier, natural endowment, natural gift, natural impulse,
   natural instinct, natural tendency, notion, parts, penchant,
   potential, power, powers, predilection, predisposition, prejudice,
   primitive self, probability, proclivity, proneness, propensity,
   qualification, quick hunch, readiness, reflex, reflex action,
   sensitivity, sensitivity to, sheer chemistry, sixth sense, skill,
   soft spot, speciality, strong flair, strong point, subconscious,
   subconscious urge, sudden thought, susceptibility, talent, talents,
   tendency, the goods, the stuff, tropism, turn, twist,
   unlearned capacity, unreasoning impulse, unwilledness, urge,
   vital impulse, warp, weakness, what it takes, willingness