Cheerios returned, disregarding church gathering (6)
I believe the answer is:
soiree
'gathering' is the definition.
(soiree is a kind of gathering)
'cheerios returned disregarding church' is the wordplay.
'SOIREE' is hidden back-to-front in amongst the letters.
But, I am unsure how this is indicated.
(Other definitions for soiree that I've seen before include "Evening function" , "Party assembled in the evening" , "A social gathering in the evening" , "Cultural at-home" .)