* Formal and Dramatic: The silence in the courtroom was portentous, suggesting a verdict of great consequence.
* Literary: The old woman's portentous words, delivered in a raspy whisper, sent shivers down their spines.
* Sarcastic: His portentous announcement about the weather was simply that: the sky looked cloudy.
* Humorous: The cat's portentous stare, accompanied by a slow blink, seemed to say, "You will be fed now, human."
Remember, "portentous" suggests something significant or ominous, often hinting at a future event.