Ritual sounds correct (4)
I believe the answer is:
rite
'ritual' is the definition.
(synonyms)
'sounds correct' is the wordplay.
'sounds' indicates a 'sounds like' (homophone) clue.
'correct' becomes 'right' (right can mean correct).
'right' is a homophone of 'RITE'.
(Other definitions for rite that I've seen before include "Formal procedure" , "Religious ceremonial sounds correct" , "Customary observance" , "something like mass" , "Ceremonial act" .)