Office frailties occasionally overlooked (4)
I believe the answer is:
rite
'office' is the definition.
(office can mean a religious ceremony or rite)
'frailties occasionally overlooked' is the wordplay.
'occasionally overlooked' means one should take alternating letters (letters removed at regular intervals).
The alternate letters of 'frailties' are 'RITE'.
(Other definitions for rite that I've seen before include "Formal procedure" , "Solemn ceremony" , "Uncomplaining person" , "Religious ceremonial sounds correct" , "Ceremony - ritual" .)