sin·​is·​ter ˈsi-nə-stər How to pronounce sinister (audio)
 archaic  sə-ˈni-
: singularly evil or productive of evil
: accompanied by or leading to disaster
: presaging ill fortune or trouble
: of, relating to, or situated to the left or on the left side of something
especially : being or relating to the side of a heraldic shield at the left of the person bearing it
: of ill omen by reason of being on the left
archaic : unfavorable, unlucky
archaic : fraudulent
sinisterly adverb
sinisterness noun

Did you know?

insidious, sinister, or pernicious?

Few would choose to be associated with people or things that are insidious, sinister, or pernicious; all three of these words have decidedly unpleasant meanings, each with its own particular shade of nastiness.

Insidious comes from a Latin word for “ambush” (insidiae), which is fitting, as this word often carries the meanings “deceitful,” “stealthy,” or “harmful in an imperceptible fashion.” The first two meanings may be applied to people or things (“an insidious enemy,” “an insidious plot”), while the last is usually applied to things (“insidious problems,” “insidious sexism”), in particular to the gradual progress of a disease (“an insidious malignancy”).

Sinister comes from a Latin word meaning “on the left side, unlucky, inauspicious.” Although it is commonly used today in the sense “evil” (“a sinister cult leader”; “a sinister plot”), it may also suggest an ominous foreshadowing of some unfavorable turn of events (“a sinister omen”).

Pernicious has largely stayed true to its etymological root, the Latin noun pernicies “ruin, destruction.” Its original meaning in English, “highly injurious or destructive,” usually applies to things (“pernicious apathy,” “pernicious effects”) and medical conditions (“pernicious fever,” “pernicious anemia”). When applied to people, pernicious means “wicked.”

Did you know?

Is sinister unfair to the left-handed?

Sinister has an etymology that might seem a bit biased against the left-handed portion of the population, as this word, which has had naught but disagreeable meanings for over five hundred years now, comes from a Latin word of the same spelling that means “on the left side.” We find this root in other English words, such as the adjective sinistral (“left-handed”) and the adverb sinistrad (“toward the left side”). To make things even more unfair, the Latin word dexter (“on the right side”) has given rise to English words with largely positive meanings, such as dexterity and ambidextrous.

Choose the Right Synonym for sinister

sinister, baleful, malign mean seriously threatening evil or disaster.

sinister suggests a general or vague feeling of fear or apprehension on the part of the observer.

a sinister aura haunts the place

baleful imputes perniciousness or destructiveness to something whether working openly or covertly.

exerting a corrupt and baleful influence

malign applies to what is inherently evil or harmful.

the malign effects of racism

Example Sentences

There was something sinister about him. the movie relies too much on sinister background music to create the suspense that the plot sorely lacks
Recent Examples on the Web British new wave hitmakers like the Human League, Adam Ant and Echo & the Bunnymen and modern, sinister electronic acts like Boy Harsher and Gvllow. August Brown, Los Angeles Times, 16 May 2023 This isn’t particularly new: His whole schtick is built on rhetorical games that demand lots of sinister hand-waving but contain little of substance. Alex Shephard, The New Republic, 11 May 2023 In the real world, lurking is a sinister thing, a behavior associated with creeps and stalkers. Elise Craig, New York Times, 9 May 2023 Regulators in multiple countries are scrutinizing OpenAI’s technology, asking questions about everything from copyright infringement to the risk of new and more sinister forms of misinformation. Gerrit De Vynck, Washington Post, 9 Apr. 2023 Packed with sinister humor, romance and horror, this show will leave you addicted. Staff Author, Peoplemag, 22 Dec. 2022 Prosthetics designer Barrie Gower was tasked with conjuring Vecna’s sinister appearance – and won an Emmy for his efforts. Partner Content, The Hollywood Reporter, 21 Dec. 2022 Things go ‘alf when wizard Gandalf the Gray reveals the storied past of the One Ring To Rule Them All, and the nefarious plan by Dark Lord Sauron to harness its sinister powers. Angelique Jackson, Variety, 12 May 2023 The plot of Beetlejuice 2 remains under-wraps, but updates are slowly coming out about the delightfully sinister sequel, including details of Jenna’s role. Leah Campano, Seventeen, 11 May 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sinister.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English sinistre, from Anglo-French senestre on the left, from Latin sinistr-, sinister on the left side, unlucky, inauspicious

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of sinister was in the 15th century

Dictionary Entries Near sinister

Cite this Entry

“Sinister.” Dictionary, Merriam-Webster, Accessed 29 May. 2023.

Kids Definition


sin·​is·​ter ˈsin-əs-tər How to pronounce sinister (audio)
: especially evil or leading to evil : bad
: threatening evil, harm, or danger : ominous
sinisterly adverb

Middle English sinistre "unlucky, unfavorable," from Latin sinistr-, sinister "left, on the left side, awkward, unfavorable"; so called because the ancient Romans believed that omens seen on the left side told of bad things to come

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