Low Tory leader undecided (4)
I believe the answer is:
moot
'undecided' is the definition.
(thesaurus)
'low tory leader' is the wordplay.
'low' becomes 'moo' ('moo' can be a synonym of 'low').
'tory leader' becomes 't' (I've seen this in other clues).
'moo'+'t'='MOOT'
(Other definitions for moot that I've seen before include "Such a point is arguable" , "raise for discussion" , "Undecided as a debatable point may be" , "Open to argument or debate" , "Such a point is disputable" .)