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sinister

American  
[sin-uh-ster] / ˈsɪn ə stər /

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 (opposed to dexter).


sinister British  
/ 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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of sinister

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

Explanation

People who are left-handed might feel unlucky having to use a desk designed for right-handers, but there probably wasn't any sinister, or evil, intent behind the design. Or was there? In the 15th century, when the word sinister came into use in English, people who were left-handed were thought to be bad luck or even evil. In his play Hamlet, Shakespeare wrote of the villain holding a human skull in his sinister — i.e., left — hand. It would seem to be sinister, or wicked, enough to see a human skull in the right hand, not to mention unlucky for the person missing a head in the first place.

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The amount of money in leveraged exchange-traded funds is also at historic highs External link, casting a sinister shadow.

From Barron's • Jul. 1, 2026

In the ballroom scene of “Swan Lake,” Mr. McKenzie’s production features a flashy and somewhat extraneous role for an alter-ego of the sinister sorcerer Von Rothbart, which Mr. Stearns has danced with poetic panache.

From The Wall Street Journal • Jun. 30, 2026

"The truth is far more sinister and darker than that."

From BBC • Jun. 18, 2026

The idea “was to create a sinister feeling that this may not end well,” he says.

From Los Angeles Times • Jun. 10, 2026

And hard as Meggie tried to see something sinister about him, she couldn’t, not in the pale morning light.

From "Inkheart" by Cornelia Funke

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