Officer's subordinate losing head after signal to pause (9)
I believe the answer is:
commander
'officer's' is the definition.
(commander is a kind of officer)
'subordinate losing head after signal to pause' is the wordplay.
'subordinate' becomes 'under' (similar in meaning).
'losing head' means to remove the first letter.
'after' says to put letters next to each other.
'signal to pause' becomes 'comma' (I've seen this in another clue).
'under' with its initial letter removed is 'nder'.
'nder' put after 'comma' is 'COMMANDER'.
(Other definitions for commander that I've seen before include "leader" , "boss" , "One in authority" , "who's already giving the orders?" , "One hoping to be captain" .)