Conceded top lawyer should buck up (6)
I believe the answer is:
agreed
'conceded' is the definition.
(I've seen this in another clue)
'top lawyer should buck up' is the wordplay.
'top lawyer' becomes 'AG' (abbreviation for attorney general).
'should buck up' becomes 'reed' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ag'+'reed'='AGREED'
Can you help me to learn more?
(Other definitions for agreed that I've seen before include "Jointly decided" , "Gave consent" , "I'll go along with that" , "Settled by common consent" , "matched" .)