a. [ Accented on the middle syllable by the older poets, as Shakespeare, Milton, Dryden. ] [ L. sinister: cf. F. sinistre. ] 1. On the left hand, or the side of the left hand; left; -- opposed to dexter, or right. “Here on his sinister cheek.” Shak. [ 1913 Webster ]

My mother's blood
Runs on the dexter cheek, and this sinister
Bounds in my father's Shak. [ 1913 Webster ]

☞ In heraldy the sinister side of an escutcheon is the side which would be on the left of the bearer of the shield, and opposite the right hand of the beholder. [ 1913 Webster ]

2. Unlucky; inauspicious; disastrous; injurious; evil; -- the left being usually regarded as the unlucky side; as, sinister influences. [ 1913 Webster ]

All the several ills that visit earth,
Brought forth by night, with a sinister birth. B. Jonson. [ 1913 Webster ]

3. Wrong, as springing from indirection or obliquity; perverse; dishonest; corrupt; as, sinister aims. [ 1913 Webster ]

Nimble and sinister tricks and shifts. Bacon. [ 1913 Webster ]

He scorns to undermine another's interest by any sinister or inferior arts. South. [ 1913 Webster ]

He read in their looks . . . sinister intentions directed particularly toward himself. Sir W. Scott. [ 1913 Webster ]

4. Indicative of lurking evil or harm; boding covert danger; as, a sinister countenance. [ 1913 Webster ]

Bar sinister. (Her.) See under Bar, n. --
Sinister aspect (Astrol.), an appearance of two planets happening according to the succession of the signs, as Saturn in Aries, and Mars in the same degree of Gemini. --
Sinister base,
Sinister chief. See under Escutcheon. [ 1913 Webster ]

a. Left-handed; hence, unlucky. [ Obs. ] Lovelace. [ 1913 Webster ]

adv. In a sinister manner. Wood. [ 1913 Webster ]