sucker punch

Noun

 * 1)  An unexpected punch or similar blow.
 * 2)  A disabling punch targeting a place which is not normally acceptable in a "fair fight", such as on the back of the head.
 * 1)  A disabling punch targeting a place which is not normally acceptable in a "fair fight", such as on the back of the head.
 * 1)  A disabling punch targeting a place which is not normally acceptable in a "fair fight", such as on the back of the head.

Verb

 * 1)  To deliver an unexpected blow.