Style in supermarket (4)
I believe the answer is:
perm
'style' is the definition.
(hair style)
'in supermarket' is the wordplay.
'in' says the answer is hidden in the clue.
'PERM' is hidden within 'supermarket'.
(Other definitions for perm that I've seen before include "Hair setting method" , "locks far from straight?" , "Football pools forecast - wavy hairdo" , "A hairdo; Urals city" , "Hair setting treatment; pools selection system" .)