Trivial like an officer (5)
I believe the answer is:
petty
This clue is a double definition.
'trivial' is the first definition.
(I know that trivial can be written as petty)
'an officer' is the second definition.
(petty officer is a kind of officer)
'like' acts as a link.
(Other definitions for petty that I've seen before include "Inferior" , "Small-time" , "This cash is of a trivial amount" , "Trivial, contemptible" , "Unimportant" .)