Adjective definite, certain
Synonyms: absolute, actual, affirmative, assured, categorical, clear, clear-cut, cocksure, cold, complete, conclusive, concrete, confident, consummate, convinced, decided, decisive, direct, downright, explicit, express, factual, firm, forceful, forcible, genuine, hard, inarguable, incontestable, incontrovertible, indisputable, indubitable, irrefutable, out-and-out, outright, perfect, rank, real, specific, sure, thorough, thoroughgoing, unambiguous, undeniable, unequivocal, unmistakable, unmitigated
Antonyms: doubtful, indefinite, negative, uncertain, unsure
Adjective beneficial, helpful
Synonyms: affirmative, constructive, effective, efficacious, forward-looking, good, practical, productive, progressive, reasonable, sound, useful
Antonyms: disadvantageous, negative, unhelpful