adjective

portentous

por-TEN-tus/pɔːrˈtentəs/

Suggesting that something of great importance is about to happen.

The portentous funnel cloud forms above the farmhouse before reaching the ground.

An ominous, low storm cloud forms a descending funnel above an isolated farmhouse; the house remains intact and the funnel has not reached the ground, making the sky a threatening sign of what may come.

Etymology

porLatinforward

+tentLatinto stretch

+ousLatinfull of

“Stretching forward” underlies foretelling, so portentous describes something charged with the significance of an omen. In the self-important sense, that weighty significance is something a person or manner projects.

In context

Storytime Haven334:31

A horrible, portentous fact was slowly looming out before her from the nebula of surmise and fear.

📖 The Blue Castle by L. M. Montgomery | A Tale of Love & Freedom 💙✨

More examples

Portentous clouds gather above the harbor.
The sudden departure of three executives seems portentous.
She announces a portentous meeting that could reshape the company.

Forms

portentous

portent noun — A sign of something important to come.

portend verb — To signal that something important will happen.

Similar words

ominous: Specifically suggests trouble or danger, not merely great importance.
prophetic: Suggests predicting future events, not simply signaling their importance.