fisticuff

Etymology
. Modern uses as a verb are a back-formation on the plural uses of the noun.

Noun

 * 1)  A fistfight.
 * 2)  A cuff or blow administered with the fist.
 * 1)  A cuff or blow administered with the fist.

Verb

 * 1)  To engage in a physical fight.
 * 2)  To strike, fight or spar with the fists.
 * 1)  To strike, fight or spar with the fists.