Rotter set out with trainee soldiers (6)
I believe the answer is:
cadets
'trainee soldiers' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps there's an association between them I don't understand?
'rotter set out' is the wordplay.
'rotter' becomes 'cad' (a cad is a dishonourable person).
'out' indicates an anagram (out can mean wrong or inaccurate).
'set' is an anagram of 'ets'.
'cad'+'ets'='CADETS'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for cadets that I've seen before include "Pupils" , "Army officer trainees" , "Trainee army officers" , "Officers potentially" , "Military trainees" .)