Adjectives

(s)portentous, prodigiousof momentous or ominous significance“such a portentous … monster raised all my curiosity” (Herman Melville), “a prodigious vision”
(s)fateful, foreboding, portentousominously prophetic
(s)grandiloquent, overblown, pompous, pontifical, portentouspuffed up with vanity“a grandiloquent and boastful manner”, “overblown oratory”, “a pompous speech”, “pseudo-scientific gobbledygook and pontifical hooey” (Newsweek)