Sheer delight (4)
I believe the answer is:
glee
'sheer delight' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for glee that I've seen before include "Happiness" , "Merriment or gloating" , "Great delight; part song" , "Joy; part-song" , "Part song for men" .)