Old judge catching one with trap to begin (9)
I believe the answer is:
Here is my best explanation:
'begin' is the definition.
'old judge catching one with trap' is the wordplay.
'old judge' becomes 'orate' (I am not sure about this - if you are sure you should believe this answer much more).
'catching' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'with' means one lot of letters go next to another.
'trap' becomes 'gin' (I've seen this before).
'orate' going around 'igin' is 'ORIGINATE'.
'to' is the link.
(Other definitions for originate that I've seen before include "Start", "Bring into existence", "Launch", "Cause to begin, be the first", "Stem", "Create; begin", "Initiate", "issue", "From kick off" and "pioneer".)