Force to show initiative (5)
I believe the answer is:
drive
I believe this is a double definition.
'force' is the first definition.
(driving is a kind of forcing)
'initiative' is the second definition.
(thesaurus)
'to show' acts as a link.
(Other definitions for drive that I've seen before include "Sales campaign - energy - push" , "Hit golf ball from tee" , "required for excursion" , "High motivation, ambition" , "natural urge" .)