Admit carbon copy record in a first trial (6)
I believe the answer is:
accept
'admit' is the definition.
(synonyms)
'carbon copy record in a first trial' is the wordplay.
'carbon copy' becomes 'cc'.
'record' becomes 'ep'.
'in' means one lot of letters goes inside another.
'first trial' becomes 't' (1st letter of 'trial').
'cc'+'ep'='ccep'
'a'+'t'='at'
'ccep' placed into 'at' is 'ACCEPT'.
(Other definitions for accept that I've seen before include "Consent to receive" , "Recognise" , "Take up, obtain" , "Bear" , "Reply in the affirmative" .)