lubricate (v.)

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 PIE *sleubh- "to slip, slide" (see sleeve). Related: Lubricated; lubricating. Earlier verb was lubrify (1610s), from Medieval Latin lubrificare.