adjective

clearly stated or decided; not vague or doubtful.

we had no definite plans

explicit,specific,express,precise,exact,defined,well defined,clear-cut,determined,fixed,established,confirmed,direct,concrete,hard,plain,outright,unmistakable,irrefutable,unequivocal,unambiguous,certain,undisputed,decided,marked,distinct,unquestioned,not in question,not in doubt