The adjective ominous describes something that worries you because it makes you think something bad is going to happen.
Synonyms are dark, sinister, threatening or inauspicious.
The word origins from Latin (1580s) ominosus meaning “full of foreboding” and from omen meaning “foreboding”.
The old woman in the street kept saying some ominous events will happen later.
The sound of the steps in the dark room implied that there will be an ominous jump scare.
The dark clouds and strong winds brought an ominous storm.