Staff trimmed in style (4,3)
I believe the answer is:
crew cut
'style' is the definition.
(I've seen this before)
'staff trimmed' is the wordplay.
'staff' becomes 'crew' (I've seen this before).
'trimmed' becomes 'cut' (synonyms).
'crew'+'cut'='CREW-CUT'
'in' acts as a link.
(Other definitions for crew cut that I've seen before include "Male hairstyle" , "top-level style" , "Style on top" , "reduced cover above" , "Closely cropped hair style for men" .)