Source : Webster's Revised Unabridged Dictionary (1913)

Stink \Stink\, v. i. [imp. & p. p. {Stunk}, {Stank}, p. pr. &
   vb. n. {Stinking}.] [AS. stinkan to have a smell (whether
   good or bad); akin to OHG. stinchan, G. & D. stinken to
   stink; of uncertain origin; cf. Icel. st["o]kkva to leap, to
   spring, Goth. stigqan to push, strike, or Gr. ? rancid. Cf.
   {Stench}.]
   To emit a strong, offensive smell; to send out a disgusting
   odor.

Stunk \Stunk\,
   imp. & p. p. of {Stink}.

Source : WordNet®

stink
     v 1: be extremely bad in quality or in one's performance; "This
          term paper stinks!"
     2: smell badly and offensively; "The building reeks of smoke"
        [syn: {reek}]
     [also: {stunk}, {stank}]

stink
     n : a distinctive odor that is offensively unpleasant [syn: {malodor},
          {malodour}, {stench}, {reek}, {fetor}, {foetor}, {mephitis}]
     [also: {stunk}, {stank}]

stunk
     See {stink}