Strongly motivated to succeed (6)
I believe the answer is:
driven
'strongly motivated to succeed' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for driven that I've seen before include "Urges or conveyed, perhaps in car" , "Forced, compelled" , "Urged or forced along" , "Strongly motivated to succeed" , "Determined" .)