Shy couple's brief relationship (5)
I believe the answer is:
fling
This clue could be a double definition.
'shy couple's' is the first definition.
'fling' can be an answer for 'shy' (thesaurus). I'm not certain of the 'couple's' bit.
'brief relationship' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for fling that I've seen before include "Throw violently" , "good time" , "Brief relationship" , "Throw angrily in spell of indulgent pleasure" , "Spell of indulgence" .)