Cardi B specialty (3)
I believe the answer is:
rap
'cardi b specialty' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rap that I've seen before include "Blame, punishment" , "Knock sharply" , "Knock; type of rhythmical speech to music" , "Form of music with chanted rhyming lyrics" , "Strike; music genre" .)