Sailor boy wearing waterproof cloth (9)
I believe the answer is:
tarpaulin
'waterproof cloth' is the definition.
(I've seen this before)
'sailor boy wearing' is the wordplay.
'sailor' becomes 'tar' (tar is a kind of sailor).
'boy' becomes 'paul' (**).
'wearing' becomes 'in' (wear in (and 'in' is fashionable)).
'tar'+'paul'+'in'='TARPAULIN'
(Other definitions for tarpaulin that I've seen before include "seaman rarely required" , "Waterproofed canvas" , "protective cover" , "Heavy waterproof canvas" , "Waterproof canvas used as covering" .)