Nitless new recruits (7)
I believe the answer is:
enlists
'recruits' is the definition.
(enlisting is a kind of recruiting)
'nitless new' is the wordplay.
'new' is an anagram indicator.
'nitless' is an anagram of 'ENLISTS'.
(Other definitions for enlists that I've seen before include "volunteers" , "Joins up" , "Recruits" , "gets involved" , "Signs up" .)