After time, managed to accept silly idiot's custom (9)
I believe the answer is:
tradition
'custom' is the definition.
(I've seen this before)
'after time managed to accept silly idiot's' is the wordplay.
'after' means one lot of letters go next to another.
'time' becomes 't'.
'managed' becomes 'ran' (I've seen this before**).
'to accept' means one lot of letters goes inside another.
'silly' is an anagram indicator.
'idiot' with letters rearranged gives 'ditio'.
'ran' placed around 'ditio' is 'radition'.
't' put next to 'radition' is 'TRADITION'.
(Other definitions for tradition that I've seen before include "Inherited pattern of thought or action" , "Practices of long standing" , "Long-established custom or belief" , "Practice of long standing" , "Body of beliefs and customs handed down through generations" .)