tending or liable to cause slipping or sliding, as ice, oil, a wet surface, etc.

a slippery road.

tending to slip from the hold or grasp or from position

a slippery rope.

likely to slip away or escape

slippery prospects.

not to be depended on; fickle; shifty, tricky, or deceitful.

unstable or insecure, as conditions

a slippery situation.