Bloke holding one army officer responsible (6)
I believe the answer is:
guilty
'responsible' is the definition.
(I've seen this before)
'bloke holding one army officer' is the wordplay.
'bloke' becomes 'guy' (I've seen this before).
'holding' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'army officer' becomes 'lt' (abbreviation for lieutenant).
'i'+'lt'='ilt'
'guy' enclosing 'ilt' is 'GUILTY'.
(Other definitions for guilty that I've seen before include "Responsible for a reprehensible act" , "Having done wrong - a plea in court" , "Jury verdict - the accused did it" , "(Found) responsible for offence" , "Justly charged" .)