Fungus with fur felt wrong (7)
I believe the answer is:
truffle
'fungus' is the definition.
(I know that truffle is a type of fungus)
'with fur felt wrong' is the wordplay.
'with' means one lot of letters go next to another.
'wrong' is an anagram indicator.
'fur' next to 'felt' is 'furfelt'.
'furfelt' is an anagram of 'TRUFFLE'.
(Other definitions for truffle that I've seen before include "2 (anag)" , "Underground delicacy" , "Rich food" , "Fungoid delicacy" , "Chocolaty sweet" .)