sinister

adjective

• 1giving the impression that something harmful or evil is happening or will happen:there was something sinister about that murmuring voice
• evil or criminal:there might be a more sinister motive behind the government’s actions

• 2 [attributive] archaic & Heraldry of, on, or towards the left-hand side (in a coat of arms, from the bearer’s point of view, i.e. the right as it is depicted). The opposite of dexter¹.