American soldier on foot is present (4)
I believe the answer is:
gift
'present' is the definition.
('gift' can be a synonym of 'present')
'american soldier on foot' is the wordplay.
'american soldier' becomes 'gi' (**).
'on' says to put letters next to each other.
'foot' becomes 'ft' ('ft' can be a synonym of 'foot').
'gi'+'ft'='GIFT'
'is' is the link.
(Other definitions for gift that I've seen before include "A present or a natural ability" , "bent" , "A present or gratuity" , "Donation" , "Endowment" .)