Criticise expert with a remedy for all ills (7)
I believe the answer is:
panacea
'remedy for all ills' is the definition.
(I've seen this before)
'criticise expert with a' is the wordplay.
'criticise' becomes 'pan' (informal term meaning to criticise heavily).
'expert' becomes 'ace' (ace is a kind of expert**).
'with' is a charade indicator (letters next to each other).
'pan'+'ace'+'a'='PANACEA'
(Other definitions for panacea that I've seen before include "fixes all complaints" , "A cure-all for diseases or troubles" , "Cure for all ills" , "Cure-all in a canape" , "that's going to help a lot" .)