Crumbs American soldier gives dog (5)
I believe the answer is:
corgi
'dog' is the definition.
(I know that corgi is a type of dog)
'crumbs american soldier' is the wordplay.
'crumbs' becomes 'cor' (both can be exclamations of shock).
'american soldier' becomes 'GI' (informal term for a US soldier).
'cor'+'gi'='CORGI'
'gives' is the link.
(Other definitions for corgi that I've seen before include "The Queen's favourite?" , "pet in 9 [CARDIFF]?" , "Little dog" , "Welsh 11" , "Barker?" .)