横柄に (translations)→ bossily impertinently
決定的に (translations)→ conclusively crucially definitively fatefully terminally unequivocally
高飛車に (translations)→ aggressively haughtily highhandedly
断固として (translations)→ forbidding stoutly sturdily unswervingly
断定的に (translations)→ assertively decisively
否応なしに (translations)→ compulsively imperatively inevitable perforce strongly willy-nilly