More likely than not (4-2)
I believe the answer is:
odds-on
'more likely than not' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for odds-on that I've seen before include "Rated likely to win" , "More likely to win than lose" , "With success more likely than favour in bookie's phrase" , "High probability" , "A better than even chance of success" .)