Shy affair (5)
I believe the answer is:
fling
I believe this is a double definition.
'shy' is the first definition.
(thesaurus)
'affair' is the second definition.
(I have seen 'Brief affair' mean 'fling' so perhaps 'affair' could also mean 'fling')
(Other definitions for fling that I've seen before include "Toss" , "quick one?" , "Throw violently" , "Throw as in Highland dance?" , "knees-up at 8 [HIGHLAND GAMES]" .)