Unappreciative person (7)
I believe the answer is:
ingrate
'unappreciative person' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ingrate that I've seen before include "Tangier (anag)" , "without a word of thanks?" , "I'm not appreciative" , "One who never says thanks" , "Thankless wretch" .)