Concurred silver buck perhaps returned (6)
I believe the answer is:
agreed
'concurred' is the definition.
('agree' can be a synonym of 'concur')
'silver buck perhaps returned' is the wordplay.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'buck perhaps' becomes 'deer' (buck can mean a male deer. I am not sure about the 'perhaps' bit.).
'returned' is a reversal indicator.
'deer' in reverse letter order is 'reed'.
'ag'+'reed'='AGREED'
Can you help me to learn more?
(Other definitions for agreed that I've seen before include "Settled by common consent" , "Was consistent" , "Consented, settled" , "Consented and concurred" , "In accord" .)