slippery

Of a surface, having low friction, often due to being covered in a non-viscous liquid, and therefore hard to grip, hard to stand on without falling, etc.

Oily substances render things slippery.

The screeching of brakes, the monotonous blare of motor horns, the clip-clip of shoes on slippery pavements, the rustling of wet mackintoshes were all part of the great metropolis.

Evasive; difficult to pin down.

a slippery person

a slippery promise

Liable to slip; not standing firm.

Which when they fall, as being slippery standers, / The love that leaned on them, as slippery too, / Do one pluck down another, and together / Die in the fall.

Unstable; changeable; inconstant.

He looking down With scorn or pity on the slippery state Of kings, will tread upon the neck of fate.

Wanton; unchaste; loose in morals.

My wife is slippery? If thou wilt confess –