9/1/19 Sucker punch

 

sucker punch (American English) is a punch made without warning or while the recipient is distracted, allowing no time for preparation or defense on the part of the recipient. It is often thrown from behind, although striking from behind is not a prerequisite for a sucker punch.
The term is generally used in situations where the way in which the punch has been delivered is considered unfair or unethical, and is done using deception or distraction, hence the term ‘sucker’ used to refer to the victim.