Skin is cut first (5)
I believe the answer is:
cutis
'skin' is the definition.
(I've seen this before)
'is cut first' is the wordplay.
'first' means one lot of letters go next to another.
'is' after 'cut' is 'CUTIS'.
(Other definitions for cutis that I've seen before include "skin, technically" , "Surface area" , "Skin, dermis" , "Technical name for skin" , "a bit skinny" .)