A military force to show aloofness (10)
I believe the answer is:
detachment
I believe this is a double definition.
'a military force' is the first definition.
(detachment is a kind of military force)
'aloofness' is the second definition.
(I've seen this before)
'to show' acts as a link.
(Other definitions for detachment that I've seen before include "indifference" , "some engaged in military action?" , "Disengagement" , "Aloofness" , "Objective state; group of troops" .)