Clairvoyance in ceremony causes delay (7)
I believe the answer is:
respite
'delay' is the definition.
(respite can mean a delay or postponement)
'clairvoyance in ceremony' is the wordplay.
'clairvoyance' becomes 'esp' (synonyms).
'in' is an insertion indicator.
'ceremony' becomes 'rite' (rite is a kind of ceremony).
'esp' put within 'rite' is 'RESPITE'.
'causes' acts as a link.
(Other definitions for respite that I've seen before include "Breathing space" , "temporary delay" , "Short break" , "Pause from pain" , "Short period of relief" .)