Real Dictionary

slippery
adjective: Something that is slippery is smooth, wet, or oily and is therefore difficult to walk on or to hold.
adjective: You can describe someone as slippery if you think that they are dishonest in a clever way and cannot be trusted.

slippery in American English
causing or liable to cause sliding or slipping, as a wet, waxed, or greasy surface
adjective: tending or liable to cause slipping or sliding, as ice, oil, a wet surface, etc.

slippery in British English
adjective: causing or tending to cause objects to slip