Something that's lewd or lascivious, like dirty pictures or skimpy clothing, can be described as lubricious. Occasionally lubricious is also used to mean tricky or sly, like a slick or lubricious used car salesman. A related meaning is "oily or slippery," like a lubricious bar of soap sitting in a puddle of water. This is actually the original meaning of the word, from the Latin root lubricus, "to make slippery or smooth."