Pass for an officer (3)
I believe the answer is:
col
I believe this clue is a double definition.
'pass' is the first definition.
(col is a kind of pass)
'an officer' is the second definition.
(short for colonel)
'for' is the link.
(Other definitions for col that I've seen before include "Mountain defile" , "Low point of a ridge" , "A pass between mountain peaks" , "Somewhere up on the mountain" , "Lowest point of ridge between two peaks" .)