Training cadet with gun I loaded (9)
I believe the answer is:
educating
'training' is the definition.
('educate' can be a synonym of 'train')
'cadet with gun i loaded' is the wordplay.
'with' says to put letters next to each other.
'loaded' indicates an anagram (loaded can mean drunk).
'gun'+'i'='guni'
'cadet' put after 'guni' is 'gunicadet'.
'gunicadet' anagrammed gives 'EDUCATING'.
(Other definitions for educating that I've seen before include "Teaching" , "Giving knowledge" , "- - Rita, film" .)