Officer showing a stout heart in the army, perhaps (5)
I believe the answer is:
mayor
'officer' is the definition.
(I've seen this before)
'a stout heart in the army perhaps' is the wordplay.
'heart' means to look at the middle letters.
'in the' indicates putting letters inside.
'perhaps' indicates anagramming the letters.
The middle letter of 'stout' is 'o'.
'army' with letters rearranged gives 'mayr'.
'o' going within 'mayr' is 'MAYOR'.
'showing' acts as a link.
(Other definitions for mayor that I've seen before include "Local bigwig" , "Head of a city council" , "For example, Henchard" , "Officer" , "City manager" .)