Dude impressed by plain entertainment (7)
I believe the answer is:
cabaret
'entertainment' is the definition.
(cabaret is a kind of entertainment)
'dude impressed by plain' is the wordplay.
I cannot quite understand how this works, but
'plain' could be 'bare' (similar in meaning) and 'bare' is found in the answer.
'dude' could be 'cat' (American slang for man, esp in Jazz) and 'cat' is found in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for cabaret that I've seen before include "Revue" , "Series of acts" , "Entertainment at restaurant" , "Nightclub 12ac" , "Entertainment at night club" .)