resolute

active adamant ardent audacious bent bolder bold brave bound and determined bravest constant courageous dauntless decisive decided determined dogged earnest faithful fast faster fastest fighting firm game grimmest grim grimmer gritty gutsy hard-nosed/hardheaded hardheaded hard-core hell-bent immovable inalterable indomitable inexorable inflexible insistent intransigent intractable intractable/intransigent intrepid liege loyal manful more constant more active more intransigent more intransigent more hardnosed more intractable more intractable more hard nosed more hard-nosed more loyal more hardheaded more hardheaded more serious more masculine most hardheaded most hardheaded most hard-nosed most hardnosed most hard nosed most intrepid most masculine most loyal most intransigent most intransigent most intractable most intractable most serious persistent pertinacious purposeful secure serious set severe sobersided spirited stable steadfast steady stouter stout strenuous strong strong-willed sturdy tenacious tireless tough tough-minded toughest tougher true unbending unchangeable unchanged uncompromising undaunted unfaltering unflinching unmoved untiring unshaken unwearied unwavering weariless