[ sin-uh-ster ]
/ ˈsɪn ə stər /
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threatening or portending evil, harm, or trouble; ominous: a sinister remark.
bad, evil, base, or wicked; fell: his sinister purposes.
unfortunate; disastrous; unfavorable: a sinister accident.
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 (opposed to dexter).



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“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

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Origin of sinister

1375–1425; late Middle English <Latin: on the left hand or side, hence unfavorable, injurious


Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for sinister

/ (ˈsɪnɪstə) /


threatening or suggesting evil or harm; ominousa 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
Compare dexter 1

Derived forms of sinister

sinisterly, adverbsinisterness, noun

Word Origin for sinister

C15: from Latin sinister on the left-hand side, considered by Roman augurs to be the unlucky one
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

Medical definitions for sinister

[ sĭnĭ-stər ]


Presaging trouble; ominous.
On the left side; left.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.