Loud, riotous game? (4)
I believe the answer is:
ludo
'game?' is the definition.
(ludo is a kind of game)
'loud riotous' is the wordplay.
'riotous' indicates an anagram.
'loud' is an anagram of 'LUDO'.
(Other definitions for ludo that I've seen before include "Traditional board game" , "Loud sort of board game with dice and counters" , "Simple board game, involving dice" , "race for four tokens" , "Race game" .)