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

“We understood the Soviet Union was an existential threat, certainly with its nuclear capabilities, it was, and Russia is, but China is even more sinister. It's more insidious in what they have done under this communist regime.”

From Salon

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

From Salon

That sinister ellipsis is Grewal’s.

From Los Angeles Times

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

Trump supporters in the US consume right wing propaganda far more than the rest of the country, which means they were either not informed about Trump’s sinister plans, or Fox and Musk succeeded in scaring them with a firehose of Harris disinformation.

From Salon

Related Words

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