Romantic infatuation (5)
I believe the answer is:
crush
'romantic infatuation' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for crush that I've seen before include "An infatuation with the orange drink?" , "Adolescent's temporary love" , "Fruit drink; crowd" , "Squash" , "Close crowd of people" .)