Slippery means so smooth or wet that feet and fingers cannot hold on. A slippery floor, slippery rocks, the road is slippery.
Ice, wet tiles, spilled oil and mossy stone are the usual causes, and slippery when wet is the standard warning sign. Of a person it means untrustworthy and hard to pin down: a slippery character, a slippery answer. The slippery slope is a very common phrase and a named argument: the claim that one small step will lead unstoppably to a much worse outcome — often a fair warning, and often a fallacy.
1adjectiveslipperySo smooth or wet that it is hard to hold or stand on.
“The steps are slippery for about an hour after the rain.”
2adjectiveuntrustworthyUntrustworthy and hard to pin down.
“He gave a slippery answer and changed the subject.”
slippery is a quality of a surface.
Slippery was built in the sixteenth century from an older adjective slipper, meaning the same thing, itself from the verb slip. The extra syllable was added for rhythm and simply stuck, which is why slipper the shoe and slippery the surface look related and only distantly are.
Middle English
slipperie
English, today
slippery
Built from
From Middle English slipperie, an extended form (-y) of Middle English slipper, sliper (“slippery”), from Old English slipor (“slippery”), from Proto-Germanic slipraz (“smooth, slippery”), equivalent to slip + -er. Compare also Middle English slibbri, slubbri (“slippery”) borrowed from Middle Dutch or Middle Low German slibberich (“slippery”). Cognate with German schlüpfrig (“slippery”), Danish slibrig (“slippery”), Swedish slipprig (“slippery”).
Etymology from Wiktionary, CC BY-SA