Stops waffling (4)
'stops waffling' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for opts that I've seen before include "Makes a choice from a range" , "Picks needed" , "Elects" , "Settles" , "Selects as an alternative" .)
(Other definitions for decides that I've seen before include "Chooses" , "Makes a resolution" , "Gives judgement" , "Fixes" , "Makes up one's mind" .)