Make extremely happy (5)
I believe the answer is:
elate
'make extremely happy' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for elate that I've seen before include "Inspirit, make exultant" , "Delight" , "Make delighted or proud" , "Lift (the spirits)" , "Uplift (mood)" .)