'Left', or 'on the left side', in Heraldry; comes straight from the Latin. Note that this is from the point of view of the bearer; to someone looking at a shield as depicted, if something is sinister it is on the right-hand side. The fact that sinister has come to refer to something slyly threatening is one of the many remnants of anti-left-handed prejudice fossilised in our language, all suggesting that there is something just 'not right' about left.

The counterpart of sinister is dexter on the right. These two give their names to Sinister Dexter of the Principia Discordia and the main characters in Sinister Dexter from the comic 2000AD (Finnigan Sinister & Ramone Dexter).

'Sinister' is also the title of a long-running Belle and Sebastian mailing list; it is named after their first album, If You're feeling Sinister, which is often called Sinister for short. The web site for it is at http://www.missprint.org/sinister/ - bear in mind that it tends to be quite high-traffic, or anyway it was when I joined up for a while some time around 1999.

Sin"is*ter (?), 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.

Shak.

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

⇒ 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.

2.

Unlucky; inauspicious; disastrous; injurious; evil; -- the left being usually regarded as the unlucky side; as, sinister influences.

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

3.

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

Nimble and sinister tricks and shifts. Bacon.

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

He read in their looks . . . sinister intentions directed particularly toward himself. Sir W. Scott.

4.

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

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.

© Webster 1913.