threatening

(verb) pose a threat to; present a danger to. Synonyms: endanger, jeopardize, jeopardise, menace, threaten, imperil, peril. Example: "The pollution is endangering the crops."

(verb) to utter intentions of injury or punishment against:"He threatened me when I tried to call the police". Synonyms: threaten.

(verb) to be a menacing indication of something:"The clouds threaten rain". Synonyms: threaten. Example: "Danger threatens."

(adj) threatening or foreshadowing evil or tragic developments. Synonyms: baleful, forbidding, menacing, minacious, minatory, ominous, sinister. Examples: "A baleful look." "Forbidding thunderclouds." "His tone became menacing." "Ominous rumblings of discontent." "Sinister storm clouds." "A sinister smile." "His threatening behavior." "Ugly black clouds." "The situation became ugly."

(adj) darkened by clouds. Synonyms: heavy, lowering, sullen. Example: "A heavy sky."