Not in the coterie for a start (6)
I believe the answer is:
outset
'for a start' is the definition.
(synonyms)
'not in the coterie' is the wordplay.
'not in' becomes 'out' ('out' is the opposite to 'in').
'the coterie' becomes 'set' (I've seen this in another clue).
'out'+'set'='OUTSET'
(Other definitions for outset that I've seen before include "Opening stage" , "Kickoff time?" , "launch" , "Set out in the beginning" , "Starting point" .)