sinister

/S IH1 N IH0 S T ER0/
adjective
  1. 1

    Inauspicious, ominous, unlucky, illegitimate (as in bar sinister).

  2. 2

    Evil or seemingly evil; indicating lurking danger or harm.

    โ€œsinister influencesโ€

  3. 3

    Of the left side.

  4. 4

    On the left side of a shield from the wearer's standpoint, and the right side to the viewer.

  5. 5

    Wrong, as springing from indirection or obliquity; perverse; dishonest.

Antonyms

Source: https://en.wiktionary.org/wiki/sinister