A party is making excuses (6)
I believe the answer is:
alibis
'excuses' is the definition.
(alibiing is a kind of excusing)
'a party is' is the wordplay.
'party' becomes 'lib' (abbreviation for Liberal, uk political party).
'a'+'lib'+'is'='ALIBIS'
'making' is the link.
(Other definitions for alibis that I've seen before include "Defences in court" , "Defences - was elsewhere at time of crimes" , "Defences of being elsewhere at the time of a crime" , "They're useful to have if accused of crimes" , "Legal defences of being somewhere else at times of crimes" .)