Such laughter can hardly be a belly laugh! (6)
I believe the answer is:
hearty
'laugh' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for hearty that I've seen before include "Stalwart" , "full of enthusiasm" , "backslapping everyone?" , "Warm, vigorous" , "Vigorously warm and friendly" .)