Cola is ordered for a party (6)
I believe the answer is:
social
'a party' is the definition.
(social is a kind of party)
'cola is ordered' is the wordplay.
'ordered' is an anagram indicator.
'cola'+'is'='colais'
'colais' is an anagram of 'SOCIAL'.
'for' acts as a link.
(Other definitions for social that I've seen before include "Informal party" , "Relating to human groups" , "Sort of security" , "Liking companionship" , "Outgoing, extroverted" .)