Source : Webster's Revised Unabridged Dictionary (1913)

Stiff \Stiff\, a. [Compar. {Stiffer}; superl. {Stiffest}.] [OE.
   stif, AS. st[=i]f; akin to D. stijf, G. steif, Dan. stiv, Sw.
   styf, Icel. st[=i]fr, Lith. stipti to be stiff; cf. L. stipes
   a post, trunk of a tree, stipare to press, compress. Cf.
   {Costive}, {Stifle}, {Stipulate}, {Stive} to stuff.]
   1. Not easily bent; not flexible or pliant; not limber or
      flaccid; rigid; firm; as, stiff wood, paper, joints.

            [They] rising on stiff pennons, tower The mid
            a["e]rial sky.                        --Milton.

   2. Not liquid or fluid; thick and tenacious; inspissated;
      neither soft nor hard; as, the paste is stiff.

   3. Firm; strong; violent; difficult to oppose; as, a stiff
      gale or breeze.

   4. Not easily subdued; unyielding; stubborn; obstinate;
      pertinacious; as, a stiff adversary.

            It is a shame to stand stiff in a foolish argument.
                                                  --Jer. Taylor.

            A war ensues: the Cretans own their cause, Stiff to
            defend their hospitable laws.         --Dryden.

   5. Not natural and easy; formal; constrained; affected;
      starched; as, stiff behavior; a stiff style.

            The French are open, familiar, and talkative; the
            Italians stiff, ceremonious, and reserved.
                                                  --Addison.

   6. Harsh; disagreeable; severe; hard to bear. [Obs. or
      Colloq.] ``This is stiff news.'' --Shak.

   7. (Naut.) Bearing a press of canvas without careening much;
      as, a stiff vessel; -- opposed to {crank}. --Totten.

   8. Very large, strong, or costly; powerful; as, a stiff
      charge; a stiff price. [Slang]

   {Stiff neck}, a condition of the neck such that the head can
      not be moved without difficulty and pain.

   Syn: Rigid; inflexible; strong; hardly; stubborn; obstinate;
        pertinacious; harsh; formal; constrained; affected;
        starched; rigorous.

Source : WordNet®

stiff
     adj 1: lacking ease in bending; not limber; "a stiff neck"; "stiff
            joints"; "stiff hairs"
     2: not moving or operating freely; "a stiff hinge"
     3: powerful; "a stiff current"; "a stiff breeze"; "a stiff
        drink"
     4: rigidly formal; "a starchy manner"; "the letter was stiff
        and formal"; "his prose has a buckram quality" [syn: {starchy},
         {buckram}]
     5: hard to overcome or surmount; "a stiff hike"; "a stiff
        exam"; "an uphill battle against a popular incumbant"
        [syn: {uphill}]
     6: of a collar; standing up rather than folded down; "an
        uncomfortable standup collar"; "a stiff collar" [syn: {stand-up}]
     7: incapable of or resistant to bending; "a rigid strip of
        metal"; "a table made of rigid plastic"; "a palace
        guardsman stiff as a poker" [syn: {rigid}]
     8: very drunk [syn: {besotted}, {blind drunk}, {blotto}, {crocked},
         {cockeyed}, {fuddled}, {loaded}, {pie-eyed}, {pissed}, {pixilated},
         {plastered}, {potty}, {slopped}, {sloshed}, {smashed}, {soaked},
         {soused}, {sozzled}, {squiffy}, {tiddly}, {tiddley}, {tight},
         {tipsy}, {wet}]

stiff
     n 1: an ordinary man; "a lucky stiff"; "a working stiff"
     2: the dead body of a human being [syn: {cadaver}, {corpse}, {clay},
         {remains}]

stiff
     adv 1: extremely; "bored stiff"; "frightened stiff"
     2: in a stiff manner; "his hands lay stiffly" [syn: {stiffly}]