Commander-in-chief takes a moment to show scar (9)
I believe the answer is:
cicatrice
'scar' is the definition.
('cicatrice' can be a synonym of 'scar')
'commander-in-chief takes a moment' is the wordplay.
'commander-in-chief' becomes 'cic'.
'takes' means one lot of letters go next to another.
'moment' becomes 'trice' (I've seen this before).
'cic'+'a'+'trice'='CICATRICE'
'to show' is the link.
(Other definitions for cicatrice that I've seen before include "something over wound" , "Scar over a healed wound" .)