Meaning: unfair blame or criticism (definition).

Example: The website got a bum rap for being difficult to reach, which was the result of a DOS attack.  (examples.)

Origins: bum as an adjective means of poor quality or useless, 19th century; rap as a term for criminal charge comes circa 1865 (History1. History 2.) 


Rewrites: bum blame bum slam twisted rap lame critique cheap lip stretched bitch
Discussion: I have gone from very close to the original to very far from it but still encasing the meaning. This one took some work with a thesaurus.