Against chanting outside (4)
I believe the answer is:
anti
'against' is the definition.
(prefix meaning against)
'chanting outside' is the wordplay.
'outside' says the answer is hidden in the clue (a word is around or outside the answer).
'ANTI' is hidden within 'chanting'.
(Other definitions for anti that I've seen before include "Prefix meaniing against" , "Who pooh-poohs all" , "on the other side" , "not favoured" , "Prefix meaning against" .)