adj.1 suggestive of evil; looking malignant or villainous.
2 wicked or criminal (a sinister motive).
3 of evil omen.
4 Heraldry of or on the left-hand side of a shield etc. (i.e. to the observer's right).
5 archaic left-hand.
Derivatives:
sinisterly adv. sinisterness n.
Etymology: ME f. OF sinistre or L sinister left