Synset

threatening or foreshadowing evil or tragic developments
<adj.all>   freq. cnt.: 16 freq. cnt.: 10 freq. cnt.: 3 freq. cnt.: 2 freq. cnt.: 1

baleful

forbidding

menacing

minacious

minatory

ominous

sinister

threatening

sample sentences

"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"