New guy on manoeuvres (5)
I believe the answer is:
young
'new' is the definition.
(similar in meaning)
'guy on manoeuvres' is the wordplay.
'manoeuvres' indicates anagramming the letters.
'guy'+'on'='guyon'
'guyon' anagrammed gives 'YOUNG'.
(Other definitions for young that I've seen before include "without experience" , "issue" , "Mormon pioneer" , "Offspring (of animals etc)" , "no wrinkly!" .)