What you'd credit a fool with being (5)
I believe the answer is:
crass
'what you'd credit a' is the definition.
I can't judge whether this definition defines the answer.
'fool with being' is the wordplay.
'fool' becomes 'ass' (both can mean a stupid person).
'with' is a charade indicator (letters next to each other).
'being' becomes 'cr' (I can't justify this - if you can you should believe this answer much more).
'ass' after 'cr' is 'CRASS'.
Can you help me to learn more?
(Other definitions for crass that I've seen before include "Coarse" , "Blundering" , "Insensitively stupid" , "Indelicate" , "Totally lacking in sensibility" .)