sinister

adj

1. Inauspicious, ominous, unlucky, illegitimate.

   “bar sinister”

   “All the several ills that visit earth / Brought forth by night, with a sinister birth.”

   “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.”

2. Evil or seemingly evil; indicating lurking danger or harm.

   “sinister influences”

   “the sinister atmosphere of the crypt”

3. (archaic)Of the left side.

   “my Mothers bloud / Runs on the dexter checke, and this ſiniſter / Bounds in my fathers:”

   “His ſicatrice, with an Embleme of warre, heere on his ſiniſter cheeke;”

   “Before the train had stopped he had decorated his sinister shirt-cuff with the inscription, ‘J. P. Huddle, The Warren, Tilfield, near Slowborough.’”

4. (archaic)Of the left side.

   “The shield was divided into five, with two coats of arms on the dexter side (the right-hand side from the point of view of the bearer of the shield)—London and Southampton—and three on the sinister side—Salisbury, Winchester and Portsmouth.”

5. (obsolete)Wrong, as springing from indirection or obliquity; perverse; dishonest.

   “Nimble and sinister tricks and shifts.”

   “He scorns to undermine another's interest by any sinister or inferior arts.”

   “He read in their looks […] sinister intentions directed particularly toward himself.”