Sadly date Republican without a chance (13)
I believe the answer is:
unpredictable
'chance' is the definition.
(thesaurus)
'sadly date republican without a' is the wordplay.
'sadly' is an anagram indicator.
'without' indicates named letters should be taken away.
'date'+'republican'='daterepublican'
'daterepublican' with 'a' removed is 'dterepublican'.
'dterepublican' is an anagram of 'UNPREDICTABLE'.
(Other definitions for unpredictable that I've seen before include "erratic" , "Changeable" , "Capricious" .)