counterpunch

Short definition from Wiktionary

Noun

1. 1
   A punch delivered in response to a previous punch by somebody else, such as an opponent in a boxing match: a return blow, a retaliatory blow.
2. 2
   A punch used in the cutting of other punches, often used to create the negative space in or around a glyph.

Verb

1. 1
   To deliver a punch designed to exploit an opponent's momentary defensive weakness caused by a punch thrown by the opponent.
2. 2
   To deliver a competitive response to an opponent designed to exploit a weakness created by the opponent's offensive efforts.