Secret coteries in new order (8)
I believe the answer is:
esoteric
'secret' is the definition.
(similar in meaning)
'coteries in new order' is the wordplay.
'in new order' indicates an anagram (I've seen this in other clues).
'coteries' with letters rearranged gives 'ESOTERIC'.
(Other definitions for esoteric that I've seen before include "needing privy" , "Arcane -- coteries (anag)" , "Inner - secret" , "known to a few" , "Private, confined to a select group" .)