Shrewd

1. Inclining to shrew; disposing to curse or scold; hence, vicious; malicious; evil; wicked; mischievous; vexatious; rough; unfair; shrewish.
2. Able or clever in practical affairs; sharp in business; astute; sharp-witted; sagacious; keen; as, a shrewd observer; a shrewd design; a shrewd reply.
3. Artful; wily; cunning; arch.