1620s, "make slippery or smooth" (especially by the application of an oil), from Latin lubricatus, past participle of lubricare "to make slippery or smooth," from lubricus "slippery; easily moved, sliding, gliding;" figuratively "uncertain, hazardous, dangerous; seductive," from suffixed form of PIE root *sleubh- "to slip, slide." Related: Lubricated; lubricating. Earlier verb was lubrify (early 15c.), from Medieval Latin lubrificare.
