Remarkably, Conservative initially isn't attending latest party (6)
I believe the answer is:
social
'party' is the definition.
(I know that social is a type of party)
'remarkably conservative initially isn't attending latest' is the wordplay.
'remarkably' becomes 'so' ('so' can mean 'remarkably' or 'very').
'conservative' becomes 'C' (UK political abbreviation).
'initially' says to take the initial letters.
The first letters of 'isnt attending latest' is 'ial'.
'so'+'c'+'ial'='SOCIAL'
(Other definitions for social that I've seen before include "Relating to people living in groups" , "Informal party" , "Needing companionship" , "Friendly - party" , "Outgoing, extroverted" .)