Contract groom listened to in court (6)
I believe the answer is:
prenup
'contract groom listened' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'to in court' is the wordplay.
'to' becomes 'pren' (I am not sure about this - if you are sure you should believe this answer much more).
'in court' becomes 'up' ('up' can mean called before a court).
'pren'+'up'='PRENUP'
Can you help me to learn more?
(Other definitions for prenup that I've seen before include "contract for union" , "Financial agreement in case of divorce made by a couple before marriage (abbr)" , "arrangement before marriage" , "Contract before marriage, in short" , "Agreement drawn up before the wedding" .)