Motivation (5)
'motivation' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for drive that I've seen before include "Use Aston Martin, say" , "Hit ball with force" , "Energy and persistence - in car?" , "Avenue" , "High motivation, ambition" .)
'motivation' is the definition.
(impetus can mean a motivation or stimulus)
This is all the clue.
(Other definitions for impetus that I've seen before include "Momentum, stimulus" , "Force that moves something along" , "Imputes to force with which a body moves" , "influence" , "Incentive - time's up (anag)" .)
'motivation' is the definition.
(I know that reason is a type of rational motive)
This is the entire clue.
(Other definitions for reason that I've seen before include "Motivation or cause" , "Sanity and logic" , "issue" , "Cause for sanity" , "Mental power to justify an act" .)