Single person who'll never settle down caught bouquet (5)
I believe the answer is:
aroma
'bouquet' is the definition.
(bouquet can mean a wine's aroma)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for aroma that I've seen before include "Scent - fragrance" , "Distinctive odour" , "Bouquet" , "Redolence" , "Odour, mostly pleasing" .)