Cheese poor, nice crackers (8)
I believe the answer is:
pecorino
'cheese' is the definition.
(I've seen this before)
'poor nice crackers' is the wordplay.
'crackers' indicates anagramming the letters (informal term for mad).
'poor'+'nice'='poornice'
'poornice' anagrammed gives 'PECORINO'.
(Other definitions for pecorino that I've seen before include "Italian cheese made from ewe's milk" , "Hard cheese!" , "Italian sheep's cheese" .)