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

Other Word Forms

• sinisterness noun
• sinisterly adverb
• unsinister adjective
• unsinisterly adverb
• unsinisterness 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

But the sinister thing about Obamacare is, and the way the architects did this, it was diabolical.

Read more on The Wall Street Journal

"There was a sinister undertone and it was difficult to build rapport," she wrote in a statement.

Read more on BBC

Over time, the prosecution said, the aliases became "rather more sinister" threatening the girl and saying they would contact her father if she did not do as Davies asked.

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The stage lights turn green, smoke rises and the speakers blare out a theme with sinister horns.

Read more on Los Angeles Times

And while most AI clips I’ve seen have been lighthearted, there’s a sinister side to the technology, where deepfakes are used to impersonate real people and steal money.

Read more on The Wall Street Journal

Related Words

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