Uncompromising senior officer being conveyed around (12)
I believe the answer is:
intransigent
'uncompromising' is the definition.
(I've seen this before)
'senior officer being conveyed around' is the wordplay.
'senior officer' becomes 'gen' (short for general, a senior army officer).
'being conveyed' becomes 'in transit' (in transit means on the move).
'around' is an insertion indicator.
'gen' placed into 'intransit' is 'INTRANSIGENT'.
(Other definitions for intransigent that I've seen before include "Diehard" , "becomes immovable" , "Unlikely to budge" , "Uncompromising" , "Stubborn" .)