Great army officer (5)

I believe the answer is:

major

I believe this is a double definition.

'great' is the first definition.
(similar in meaning)

'army officer' is the second definition.
(I've seen this in another clue)

(Other definitions for major that I've seen before include "Significant; rank" , "John --, prime minister" , "5,27 [PRIME MINISTER]" , "Officer - of greater importance" , "Officer with crown" .)

I've seen this clue in The Sun.

Want a hint initially instead of a full solution? Install my app