1. the sound of a hit or punch 2. verb (slang) to have sexual intercourse (with someone) 3. noun (plural boffs), a big laugh 4. a line in a film etc that elicits such a laugh
onomatopoeia: 1. the naming of a thing or action by a vocal imitation of the sound associated with it (as buzz, hiss) 2. the use of words whose sound suggests the sense