Laugh gleefully (7)
I believe the answer is:
chortle
'laugh gleefully' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for chortle that I've seen before include "Laugh out loud" , "Titter" , "Joyous chuckle" , "Loud gleeful chuckle" , "Noisy gleeful laugh" .)