Holds party without par, being rash (5)
I believe the answer is:
hasty
'being rash' is the definition.
(I've seen this before)
'holds party without par' is the wordplay.
'holds' becomes 'has' ('have' can be a synonym of 'hold').
'without' suggests deleting specific letters.
'party' with 'par' removed is 'ty'.
'has'+'ty'='HASTY'
(Other definitions for hasty that I've seen before include "Rash; hurried" , "Rash; thoughtless" , "Too hurried, careless" , "Rashly quick" , "Quick - reckless" .)