Universal laughter after relative makes a fuss (8)
I believe the answer is:
brouhaha
'a fuss' is the definition.
(thesaurus)
'universal laughter after relative' is the wordplay.
'universal' becomes 'u'.
'laughter' becomes 'haha' (ha-ha is a kind of laughter).
'after' says to put letters next to each other.
'relative' becomes 'bro' (I've seen this before).
'u'+'haha'='uhaha'
'uhaha' put after 'bro' is 'BROUHAHA'.
'makes' is the link.
(Other definitions for brouhaha that I've seen before include "'Confused disturbance, uproar (8)'" , "Outcry" , "Noisy fuss" , "Storm" , "Stir" .)