Soldier very quiet about EU surrender (4,2)
I believe the answer is:
give up
'surrender' is the definition.
(synonyms)
'soldier very quiet about eu' is the wordplay.
'soldier' becomes 'gi' (term for US soldier).
'very' becomes 'v' (common abbreviation).
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'about' means one lot of letters go next to another.
'p' after 'eu' is 'eup'.
'gi'+'v'+'eup'='GIVE UP'
(Other definitions for give up that I've seen before include "Abandon; cede" , "Surrender or abandon hope" , "Cease trying" , "Cede, forego" , "Renounce or yield" .)