1. rap back - Noun
2. rap back - Verb
rap back (plural rap backs)
(US) A notification that someone who previously passed a fingerprinting or background check has since been arrested or otherwise done something that may have or would have changed the results of the earlier check.
rap back (third-person singular simple present raps back, present participle rapping back, simple past and past participle rapped back)
(transitive) To return by rappelling.