Oft repeated ceremony on the third of October (5)
I believe the answer is:
trite
'oft repeated' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs can sometimes mean the same thing.
'ceremony on the third of october' is the wordplay.
'ceremony' becomes 'rite' (rite is a kind of ceremony).
'on' is a charade indicator (letters next to each other).
'the third of october' becomes 't' (3rd letter of 'october').
'rite' after 't' is 'TRITE'.
Can you help me to learn more?
(Other definitions for trite that I've seen before include "Overfamiliar through overuse" , "used till novelty's worn off" , "Commonplace, hackneyed" , "Stock" , "repeated too often" .)