Seafood cut back severely (8)
I believe the answer is:
pilchard
'seafood' is the definition.
(pilchard is a kind of seafood)
'cut back severely' is the wordplay.
'cut' becomes 'clip' (clip is a kind of cut**).
'back' is a reversal indicator.
'severely' becomes 'hard' ('hard' can be a synonym of 'severely').
'clip' in reverse letter order is 'pilc'.
'pilc'+'hard'='PILCHARD'
(Other definitions for pilchard that I've seen before include "Fish of herring family" , "Item of seafood" , "Small marine food fish" , "Edible herring relative" , "Small fatty fish, usually tinned" .)