Confused, as it's group contentment (12)
I believe the answer is:
satisfaction
'contentment' is the definition.
(satisfaction is a kind of contentment)
'confused as it's group' is the wordplay.
'confused' indicates an anagram.
'it's' becomes ''tis' (I've seen this before).
'group' becomes 'faction' ().
'as' with letters rearranged gives 'sa'.
'sa'+'tis'+'faction'='SATISFACTION'
(Other definitions for satisfaction that I've seen before include "I can't get no - (Rolling Stones)" , "Pleasure" , "Contentment; reparation" , "Fulfilment; compensation" , "Gratification" .)