One who wallows in merrymaking? (8)
I believe the answer is:
reveller
'one who wallows' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'merrymaking?' is the wordplay.
I cannot really understand how this works, but
'merrymaking?' could be 'revel' (revel is a kind of merrymaking) and 'revel' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'in' is the link.
Can you help me to learn more?
(Other definitions for reveller that I've seen before include "One who carouses or parties" , "Merrymaker, loud party-goer" , "Party girl" , "Carouser, merrymaker" , "Noisy party-goer" .)