sinister

Etymology

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

adj

1. Inauspicious, ominous, unlucky, illegitimate (as in bar sinister).
   And in the meanwhile, Society shivered a little feverishly, filled now with the scions of those who had come over with the Jewish and American Conquests. Escutcheons were becoming valueless, how sinister soever the blots and clots upon them. 1922, Michael Arlen, “1/5/1”, in “Piracy”: A Romantic Chronicle of These Days
2. Evil or seemingly evil; indicating lurking danger or harm.
   sinister influences
   the sinister atmosphere of the crypt
3. (archaic) Of the left side.
   Before the train had stopped he had decorated his sinister shirt-cuff with the inscription, ‘J. P. Huddle, The Warren, Tilfield, near Slowborough.’ 1911, Saki, ‘The Unrest-Cure’, The Chronicles of Clovis
4. (heraldry) On the left side of a shield from the wearer's standpoint, and the right side to the viewer.
5. (obsolete) Wrong, as springing from indirection or obliquity; perverse; dishonest.
   He scorns to undermine another's interest by any sinister or inferior arts. 1667, Robert South, The Practice of Religion Enforced by Reason