English Reference
adjective

sinister

adj.
US /ˈsɪnɪstɝ/ UK /sˈɪnɪstɐ/ sin·is·ter

  1. 01 B2 Upper Intermediate

    giving the impression that something evil or harmful is happening or will happen.

    suggesting or threatening evil, harm, or trouble. Often used to describe an atmosphere, a person's expression, or a mysterious event.

    Simple

    There was a sinister figure standing in the shadows at the end of the street.

    In context

    The abandoned mansion had a sinister atmosphere that discouraged even the most curious teenagers from approaching its gates after dark.

  2. 02 C2 Proficiency TechnicalArchaic

    relating to the left side of a shield or coat of arms.

    pertaining to the left side of a heraldic shield from the perspective of the bearer, which appears as the right side to the observer.

    Simple

    The knight's shield featured a red stripe on the sinister side.

    In context

    The genealogist noted a bend sinister on the family crest, a traditional heraldic mark often associated with illegitimate lineage.

    Usage

    In heraldry, 'sinister' is the opposite of 'dexter'.

  3. 03 C1 Advanced LiteraryFormal

    dishonest or sneaky in a way that is hard to see.

    characterised by deviousness, dishonesty, or underhanded motives. This sense is less about physical threat and more about moral corruption.

    Simple

    The politician had a sinister plan to win the election by cheating.

    In context

    The investigation uncovered a sinister plot to embezzle funds from the charity through a series of complex offshore accounts.

    deviouscorruptunderhanded

Did Lindsay Clancy kill kids over mental health or something more sinister?

Toronto Sun· 31 Aug 2026

From Middle English sinistre (“unlucky”), from Old French senestre, sinistre (“left”), from Latin sinister (“left hand”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin sinister
Level B2 · Upper Intermediate
Frequency Frequent
Updated