Pagan one at some future point hosting party (8)
I believe the answer is:
idolater
'pagan' is the definition.
(idolater is a kind of pagan)
'one at some future point hosting party' is the wordplay.
'one' becomes 'i' (Roman numeral).
'at some future point' becomes 'later'.
'hosting' indicates putting letters inside.
'party' becomes 'do' (do is a kind of party).
'i'+'later'='ilater'
'ilater' going around 'do' is 'IDOLATER'.
(Other definitions for idolater that I've seen before include "Tailored like pagan worshipper" , "False worshipper; tailored (anag.)" , "Tailored for image worshipper" , "Worshipper of false gods" , "Tailored to worshipper of graven images" .)