. . . as the makings of a junior officer (5)
I believe the answer is:
cadet
'makings of a junior officer' is the definition.
'cadet' can be an answer for 'officer' (I have seen 'Potential officer ' mean 'cadet' so perhaps 'officer' could also mean 'cadet'). I am not certain of the 'makings of a junior' bit.
'as the' is the wordplay.
'as' becomes 'cade' (I am not sure about this - if you are sure you should believe this answer much more).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'cade'+'t'='CADET'
Can you help me to learn more?
(Other definitions for cadet that I've seen before include "officer of the future" , "young soldier" , "junior role" , "One taking instructions" , "Officer-trainee" .)