sinister

adjective

sin·​is·​ter ˈsi-nə-stər 

archaic sə-ˈni-

1

: singularly evil or productive of evil

2

: accompanied by or leading to disaster

3

: presaging ill fortune or trouble

4

a

: 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

b

: of ill omen by reason of being on the left

5

archaic : unfavorable, unlucky

6

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.

Synonyms of sinister

• ominous
• menacing

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

Examples of sinister in a Sentence

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

In the more familiar galaxy far, far away, their friends Hera Syndulla, Ezra Bridger, Zeb Orrelios and Chopper must face the powerful Grand Admiral Thrawn and his sinister allies, who seek to plunge the fledgling New Republic into war. — Angeline Jane Bernabe, ABC News, 15 Aug. 2026

The clip released last night shows this is a more complex, sinister strategist than Josh Brolin’s crash-bang-boom baddie Thanos from the previous Avengers pics. — Anthony D'alessandro, Deadline, 15 Aug. 2026

Rebecca seems sinister but is also tantalizing, especially to Eileen (Thomasin McKenzie), a shy secretary who becomes Rebecca’s… confidant? — Chris Bellamy, Entertainment Weekly, 14 Aug. 2026

Jordan Roth plays Bentley’s somewhat sinister, sometimes helpful right hand kitted out post-glam Bowie style. — Robert Lloyd, Los Angeles Times, 5 Aug. 2026

Word History

Etymology

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

Phrases Containing sinister

• bar sinister
• bend sinister

Rhymes for sinister

• minister
• administer

Kids Definition

sinister

adjective

sin·​is·​ter ˈsin-əs-tər 

1

: especially evil or leading to evil : bad

2

: threatening evil, harm, or danger : ominous

sinisterly adverb

Etymology

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