Waste odds before final (5)
I believe the answer is:
spend
'waste' is the definition.
(thesaurus)
'odds before final' is the wordplay.
'odds' becomes 'sp' (betting abbreviation for starting price).
'before' means one lot of letters go next to another.
'final' becomes 'end' ('end' can be a synonym of 'final').
'sp'+'end'='SPEND'
(Other definitions for spend that I've seen before include "Use (money etc)" , "Pass time or pay out" , "Part with money" , "Pay out (on goods)" , "While away" .)