Source : Webster's Revised Unabridged Dictionary (1913)

Spank \Spank\, v. t. [imp. & p. p. {Spanked}; p. pr. & vb. n.
   {Spanking}.] [Of unknown origin; cf. LG. spakken, spenkern,
   to run and spring about quickly.]
   To strike, as the breech, with the open hand; to slap.

Spank \Spank\, n.
   A blow with the open hand; a slap.

Spank \Spank\, v. i.
   To move with a quick, lively step between a trot and gallop;
   to move quickly. --Thackeray.

Source : WordNet®

spank
     n : a slap with the flat of the hand
     v : give a spanking to; subject to a spanking [syn: {paddle}, {larrup}]