1. sinister - Adjective
2. sinister - Adjective Satellite
On the left hand, or the side of the left hand; left; -- opposed to dexter, or right.
Unlucky; inauspicious; disastrous; injurious; evil; -- the left being usually regarded as the unlucky side; as, sinister influences.
Wrong, as springing from indirection or obliquity; perverse; dishonest; corrupt; as, sinister aims.
Indicative of lurking evil or harm; boding covert danger; as, a sinister countenance.
Source: Webster's dictionarya baleful look Source: Internet
forbidding thunderclouds Source: Internet
his tone became menacing Source: Internet
ominous rumblings of discontent Source: Internet
sinister storm clouds Source: Internet
a sinister smile Source: Internet