sinister
Americanadjective
-
threatening or portending evil, harm, or trouble; ominous.
a sinister remark.
- Synonyms:
- portentous, inauspicious
- Antonyms:
- benign
-
bad, evil, base, or wicked; fell.
his sinister purposes.
-
unfortunate; disastrous; unfavorable.
a sinister accident.
- Synonyms:
- unlucky
- Antonyms:
- favorable
-
of or on the left side; left.
-
Heraldry. noting the side of an escutcheon or achievement of arms that is to the left of the bearer (dexter ).
adjective
-
threatening or suggesting evil or harm; ominous
a sinister glance
-
evil or treacherous, esp in a mysterious way
-
(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
-
archaic located on the left side
-
archaic (of signs, omens, etc) unfavourable
Other Word Forms
- sinisterly adverb
- sinisterness noun
- unsinister adjective
- unsinisterly adverb
- unsinisterness noun
Etymology
Origin of sinister
First recorded in 1375–1425; late Middle English, from Latin: “on the left hand or side,” hence, “unfavorable, injurious”
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 childish scribbling handwriting is also a red herring for some of the more serious and sinister themes in the book, “ says Cash.
From Los Angeles Times • Mar. 16, 2026
This fourth problem makes the first three look like sinister, rather than innocent, bureaucratic snafus.
From Salon • Mar. 5, 2026
“We would interpret the correction signal activation as warning of a potential further short-term correction in the S&P 500 to test the 200-day moving average support, rather than anything more sinister for now.”
From MarketWatch • Mar. 5, 2026
He also accused Iran of "pursuing sinister nuclear ambitions", though Tehran has always insisted its programme is for civilian purposes.
From Barron's • Feb. 27, 2026
Others held a more sinister opinion, sure that some malevolent creature had dragged him from his bed.
From "Beasts of Prey" by Ayana Gray
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
