WordNet sense 1 (tenaciously unwilling or marked by tenacious unwillingness to yield):

obstinate, stubborn, unregenerate

WordNet sense 2 (determined or decided upon as by an authority):

set, dictated

WordNet sense 3 (established or decided beyond dispute or doubt):

settled

WordNet sense 4 (firm in purpose or belief; characterized by firmness and determination):

resolute

WordNet sense 5 (strongly motivated to succeed):

compulsive, driven