Example : The Florida eagles have a fierce baleful look.

Synonyms : baneful

Example : 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.

Synonyms : forbidding, menacing, minacious, minatory, ominous, sinister, threatening