Study specifically to be an officer? (5)
I believe the answer is:
major
This could be a double definition.
'study specifically' is the first definition.
'major' can be an answer for 'study' (thesaurus). I'm unsure of the 'specifically' bit.
'an officer?' is the second definition.
(major is a kind of officer)
'to be' is the link.
Can you help me to learn more?
(Other definitions for major that I've seen before include "Pre-eminent" , "Large" , "Of greater importance or stature" , "Important; old Animal Farm boar" , "Important; rank" .)