1. [n]  a person who is gullible and easy to take advantage of
2. [n]  a person who lacks good judgment
3. [n]  a professional clown employed to entertain a king or nobleman in the middle ages
4. [v]  indulge in horseplay; "Enough horsing around--let's get back to work!"; "The bored children were fooling about"
5. [v]  fool or hoax; "The immigrant was duped because he trusted everyone"; "You can't fool me!"
6. [v]  spend frivolously and unwisely; "Fritter away one's inheritance"
7. [v]  make a fool or dupe of

1. \Fool\, n. [Cf. F. fouler to tread, crush. Cf. 1st {Foil}.]
   A compound of gooseberries scalded and crushed, with cream;
   -- commonly called gooseberry fool.
   

2. \Fool\, n. [OE. fol, n. & adj., F. fol, fou, foolish, mad;
   a fool, prob. fr. L. follis a bellows, wind bag, an inflated
   ball; perh. akin to E. bellows. Cf. {Folly}, {Follicle}.]
   1. One destitute of reason, or of the common powers of
      understanding; an idiot; a natural.
   2. A person deficient in intellect; one who acts absurdly, or
      pursues a course contrary to the dictates of wisdom; one
      without judgment; a simpleton; a dolt.
            Extol not riches, then, the toil of fools. --Milton.
            Experience keeps a dear school, but fools will learn
            in no other.                          --Franklin.
   3. (Script.) One who acts contrary to moral and religious
      wisdom; a wicked person.
            The fool hath said in his heart, There is no God.
                                                  --Ps. xiv. 1.
   4. One who counterfeits folly; a professional jester or
      buffoon; a retainer formerly kept to make sport, dressed
      fantastically in motley, with ridiculous accouterments.
            Can they think me . . . their fool or jester?
                                                  --Milton.
   {April fool}, {Court fool}, etc. See under {April}, {Court},
      etc.
   {Fool's cap}, a cap or hood to which bells were usually
      attached, formerly worn by professional jesters.
   {Fool's errand}, an unreasonable, silly, profitless adventure
      or undertaking.
   {Fool's gold}, iron or copper pyrites, resembling gold in
      color.
   {Fool's paradise}, a name applied to a limbo (see under
      {Limbo}) popularly believed to be the region of vanity and
      nonsense. Hence, any foolish pleasure or condition of vain
      self-satistaction.
   {Fool's parsley} (Bot.), an annual umbelliferous plant
      ({[AE]thusa Cynapium}) resembling parsley, but nauseous
      and poisonous.
   {To make a fool of}, to render ridiculous; to outwit; to
      shame. [Colloq.]
   {To play the fool}, to act the buffoon; to act a foolish
      part. ``I have played the fool, and have erred
      exceedingly.'' --1 Sam. xxvi. 21.
   

3. \Fool\, v. i. [imp. & p. p. {Fooled}; p. pr. & vb. n.
   {Fooling}.]
   To play the fool; to trifle; to toy; to spend time in idle
   sport or mirth.
      Is this a time for fooling?                 --Dryden.
   

4. \Fool\, v. t.
   1. To infatuate; to make foolish. --Shak.
            For, fooled with hope, men favor the deceit.
                                                  --Dryden.
   2. To use as a fool; to deceive in a shameful or mortifying
      manner; to impose upon; to cheat by inspiring foolish
      confidence; as, to fool one out of his money.
            You are fooled, discarded, and shook off By him for
            whom these shames ye underwent.       --Shak.
   {To fool away}, to get rid of foolishly; to spend in trifles,
      idleness, folly, or without advantage.
   

Fool's Lisp. A small Scheme interpreter.