sinister
adjective
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.
Examples of sinister in a Sentence
Jesse Hassenger, Entertainment Weekly, 28 May 2026
Season One Finale Of ‘The Boroughs,’ Explained After uncovering the sinister conspiracy, the group seek to kill Mother and end the suffering of the town’s residents, who are suffering neurological damage from the constant draining of their brain fluid.
—Dani Di Placido, Forbes.com, 28 May 2026
And that can be particularly useful when dramatizing moments that should feel a little off, or when some sinister force is invading the characters’ space.
—Sarah Shachat, IndieWire, 28 May 2026
As the game progresses, Mina slowly becomes aware of some negative side effects from these generators and the sinister actions being taken to cover up those effects.
—ArsTechnica, 27 May 2026
See All Example Sentences for sinister
Cite this Entry
“Sinister.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sinister. Accessed 31 May. 2026.
Copy CitationKids Definition
sinister
adjective
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
