portentous

Universal Words adjective 1 (literary) important as a sign or a warning of sth that is going to happen in the future, especially when it is sth unpleasant: a portentous dream / sign 2 (formal, disapproving) very serious and intended to impress people: a portentous remark / voice portentously adverb: She frowned portentously to add weight to her suggestion. portentousness noun [U]