Raincoat flash hiding the man's virility (8)
I believe the answer is:
machismo
'virility' is the definition.
(I've seen this before)
'raincoat flash hiding the man's' is the wordplay.
'raincoat' becomes 'mac' (macintosh is a type of raincoat).
'flash' becomes 'mo' (both mean a very short period of time).
'hiding' is an insertion indicator.
'the man's' becomes 'his' (belonging to a man).
'mac'+'mo'='macmo'
'macmo' enclosing 'his' is 'MACHISMO'.
(Other definitions for machismo that I've seen before include "A show of virility or manliness" , "large injection of testosterone!" , "Cult of masculinity" , "Expression of male pride" , "strength" .)