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.
(figuratively, by extension) Evasive; difficult to pin down.a slippery persona slippery promise
(obsolete) Liable to slip; not standing firm.
1602, William Shakespeare, , III. iii. 84: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.
