Sneer at shabby grave (7)
I believe the answer is:
earnest
'grave' is the definition.
(I've seen this before)
'sneer at shabby' is the wordplay.
'shabby' indicates anagramming the letters.
'sneer'+'at'='sneerat'
'sneerat' with letters rearranged gives 'EARNEST'.
(Other definitions for earnest that I've seen before include "serious attention" , "Serious - money deposit" , "Solemn; pledge" , "Oscar Wilde wrote ''The importance of Being . . . . . . . '' (7)" , "Determined - heartfelt" .)