Sinister

·adj On the left hand, or the side of the left hand; left;

— opposed to dexter, or right.

II. Sinister ·adj Indicative of lurking evil or harm; boding covert danger; as, a sinister countenance.

III. Sinister ·adj Wrong, as springing from indirection or obliquity; perverse; dishonest; corrupt; as, sinister aims.

IV. Sinister ·adj Unlucky; inauspicious; disastrous; injurious; evil;

— the left being usually regarded as the unlucky side; as, sinister influences.

sinister
sĭnister, tra, trum (comp. sinisterior; sup. sinistimus, Prisc. pp. 605 and 607 P.; Fest. s. v. dext...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
sinister
sinister tra, trum, adj., with comp.a double comp.of uncertain origin, left, on the left, on the l...

An Elementary Latin Dictionary
Sinister-handed
·adj Left-handed; hence, unlucky. ...

Webster's Dictionary of the English Language