Which word best describes something that is "ominous"?

The term "ominous" conveys a sense of foreboding or an indication that something bad or unpleasant is likely to happen. Therefore, the word "significantly important and dangerous" aligns closely with this definition, as it emphasizes the seriousness and potential threat associated with an ominous situation or warning. This quality generates a feeling of anxiety or apprehension about future events that may be harmful or adverse.

In contrast, options that describe something as relatively unimportant, routine and predictable, or unlikely to occur do not capture the weight and urgency associated with the concept of something being ominous. They lack the inherent danger or significant importance that the correct choice conveys, as they suggest triviality, predictability, or improbability rather than a forewarning of something serious or harmful.