Character from Kuwait, cheerful (5)
I believe the answer is:
aitch
'character' is the definition.
(aitch is a kind of character)
'from kuwait cheerful' is the wordplay.
'from' says the answer is hidden in the clue.
'AITCH' can be found hidden inside 'kuwait cheerful'.
(Other definitions for aitch that I've seen before include "character leading heroes" , "Letter sound that's often dropped?" , "It's dropped by Cockneys" , "that I will immediately succeed" , "8th letter of the alphabet" .)