Gaga (8)
I believe the answer is:
besotted
'gaga' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for besotted that I've seen before include "Doting" , "Foolishly infatuated" , "Stupefied by infatuation" , "Infatuated - so betted accordingly" , "Strongly infatuated" .)