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' (abbreviation).
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'about' says to put letters next to each other.
'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" .)