sinister

[ sin-uh-ster ]

adjective

1. threatening or portending evil, harm, or trouble; ominous:

   a sinister remark.

   Synonyms: portentous, inauspicious

   Antonyms: benign

2. bad, evil, base, or wicked; fell:

   his sinister purposes.

3. unfortunate; disastrous; unfavorable:

   a sinister accident.

   Synonyms: unlucky

   Antonyms: favorable

4. of or on the left side; left.
5. Heraldry. noting the side of an escutcheon or achievement of arms that is to the left of the bearer ( dexter ).

sinister

/ ˈsɪnɪstə /

adjective

1. threatening or suggesting evil or harm; ominous

   a sinister glance

2. evil or treacherous, esp in a mysterious way
3. usually postpositive heraldry of, on, or starting from the left side from the bearer's point of view and therefore on the spectator's right
4. archaic.
   located on the left side
5. archaic.
   (of signs, omens, etc) unfavourable

Derived Forms

• ˈsinisterness, noun
• ˈsinisterly, adverb

Other Words From

• sinis·ter·ly adverb
• sinis·ter·ness noun
• un·sinis·ter adjective
• un·sinis·ter·ly adverb
• un·sinis·ter·ness noun

Word History and Origins

Origin of sinister¹

First recorded in 1375–1425; late Middle English, from Latin: “on the left hand or side,” hence, “unfavorable, injurious”

Word History and Origins

Origin of sinister¹

C15: from Latin sinister on the left-hand side, considered by Roman augurs to be the unlucky one

Example Sentences

With imprisoned Feathers possessing alarmingly honed hacking skills, however, sinister doings will soon be afoot.

From Los Angeles Times

But the “digital arrest” scam stands out as especially elaborate and sinister - meticulously planned, relentless, and invasive to every part of a victim's life.

From BBC

“You will not be thinking about abortion” may have even more sinister undertones.

From Salon

His regressive agenda was even given a sinister name — Project 2025 — and published online, where anyone could read the plans to shrink workers' paychecks, ban abortion nationwide, and decimate access to health care.

From Salon

“For the past nine years, we’ve been fighting against the most sinister and corrupt forces on Earth,” he told the crowd.

From Los Angeles Times

Related Words

• dire
• evil
• malevolent
• mischievous
• ominous
• perverse
• threatening