Ornament behind a French strip (7)
I believe the answer is:
undress
'strip' is the definition.
(I know that strip can be written as undress)
'ornament behind a french' is the wordplay.
'ornament' becomes 'dress' (dressing is a kind of ornamenting).
'behind' means one lot of letters go next to another.
'a french' becomes 'un' ('a' in French).
'dress' after 'un' is 'UNDRESS'.
(Other definitions for undress that I've seen before include "Remove clothes, strip" , "Disrobe - uniform for ordinary occasions" , "Remove one's clothes" , "Sunders (anag)" , "Divest of clothes" .)