1. Threatening or foreshadowing evil or tragic developments
   "ominous rumblings of discontent"
   - baleful, forbidding, menacing, minacious, minatory, sinister, threatening 
2. Presaging ill fortune
   "a dead and ominous silence prevailed"
   - ill, inauspicious

See also: alarming, omen, ominously, unpropitious

Encyclopedia: Ominous

• indetermination
• index
• index case
• index finger
• index fossil
• index fund
• index number
• index of refraction
• index register
• index-linked
• indexation
• indexer
• indexical
• indexing
• indexless
• India
• India ink
• india paper
• India rubber
• India-rubber fig
• India-rubber plant
• India-rubber tree
• Indiaman
• Indian
• Indian agent