Something that is portentous is important in indicating or affecting future events. In social politics, too, the city's contribution to 20th century thought and culture was no less portentous
puffed up with vanity; "a grandiloquent and boastful manner"; "overblown oratory"; "a pompous speech"; "pseudo-scientific gobbledygook and pontifical hooey"- Newsweek
disapproval If someone's way of speaking, writing, or behaving is portentous, they speak, write, or behave more seriously than necessary because they want to impress other people. There was nothing portentous or solemn about him. He was bubbling with humour. portentous prose. = pompous + portentously por·ten·tous·ly `The difference is,' he said portentously, `you are Anglo-Saxons, we are Latins.'