It's not many (3)
I believe the answer is:
few
'it's not many' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for few that I've seen before include "Hardly anyone" , "Relatively small number" , "Indefinite small amount" , "Only one or two" , "'''Many are called but ... are chosen'' (Bible) (3)'" .)