The most common and most likely answer to this crossword clue is the 5 letter word BLAME
B
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A
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Buddy explains!

The straight part
We know that "Rap" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rap = blame.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BLAME mean?
BLAME noun- Censure.
- Culpability for something negative or undesirable.
- Responsibility for something meriting censure.
- A source control feature that can show which user was responsible for a particular portion of the source code.
- To censure (someone or something); to criticize.
- To bring into disrepute.
- (usually followed by "for") To assert or consider that someone is the cause of something negative; to place blame, to attribute responsibility (for something negative or for doing something negative).