His powers, as you heard, were surprisingly well-developed for such a young wizard and — most interestingly and ominously of all — he had already discovered that he had some measure of control over them
An immense chimney, relic of a disused mill, reared up, shadowy and ominous.
He had stopped coming to meals at the staff table, an ominous sign, and on the few occasions when they had passed him in the corridors or out in the grounds, he had mysteriously failed to notice them or hear their greetings.
Before anybody could respond to this ominous pronouncement, tindormitory doors opened again and Mr. and Mrs. Weasley hurried up the ward.
Ominously, there were many cob-webbed boxes piled on a table where Harry was clearly supposed to sit; they had an aura of tedious, hard, and pointless work about them.
The careless way in which Voldemort regarded this Horcrux seemed most ominous to me.
I’m starving," said Harry, once the door had closed behind them and they were hurrying through the dark and deserted grounds; he had abandoned the rock cake after an ominous cracking noise from one of his back teeth.
There are no more uses of "ominous" in the book.
Show samples from other sources
I’m beginning to hear ominous rumblings of discontent.
With the clouds looking so ominous, I’m afraid there will be a bad storm.