Try new offer and wait, ultimately (6)
I believe the answer is:
'try' is the definition.
('effort' can be a synonym of 'try')
'new offer and wait ultimately' is the wordplay.
'new' indicates anagramming the letters.
'and' is a charade indicator (letters next to each other).
'ultimately' indicates one should take the final letters.
The final letter of 'wait' is 't'.
'offer' anagrammed gives 'effor'.
(Other definitions for effort that I've seen before include "The use of physical or mental energy" , "Attempt, endeavour" , "A bid or endeavour" , "Work - application" , "Vigorous attempt" .)