C2 adjective /pɔːrˈtɛntəs/
portentous
portentoso, grave
Meaning
Giving a sign or warning that something, often bad or serious, is going to happen; or overly solemn and pompous.
Example
His portentous tone made everyone nervous about the news.
Su tono portentoso hizo que todos se pusieran nerviosos por las noticias.