slippery

Slippery describes a surface or object that offers little grip due to low friction, making it easy to slide or lose grip. It can describe materials with a smooth, polished finish or surfaces coated with liquid or oil. The term is also used metaphorically to describe situations or people who are difficult to pin down or hold accountable.

Friction is the resisting force between contacting surfaces. Slipperiness is quantified by a coefficient of friction; lower COF means higher slipperiness. Factors include surface texture, presence of moisture, oil, soap, or ice; temperature; and load or pressure. Some materials are inherently smooth and shiny; others become slippery when wet.

Slippery conditions are common on icy roads, wet floors, waxed floors, polished metal, or sidewalks after rainfall. Safety strategies include footwear with good tread, anti-slip coatings, mats, warning signs, and techniques like walking with short steps and avoiding sudden movements. In workplaces and public spaces, improving slip resistance can reduce fall injuries.

Institutions measure slip resistance using tests such as the pendulum test or tribometer methods; results are reported as coefficients of friction or pendulum test values. Standards vary by region and application, with many guidelines specifying minimum slip-resistance thresholds for floors, stairs, and other walking surfaces.

In idiomatic use, “slippery” can describe a situation or person who evades definition, accountability, or scrutiny, as in “a slippery customer” or “a slippery slope” referring to an argument or chain of events that becomes harder to control or predict.