lubricant (adj.)

"reducing friction," 1809, from Latin lubricantem (nominative lubricans), present participle of lubricare "to make slippery or smooth," from lubricus "slippery; easily moved, sliding, gliding;" figuratively "uncertain, hazardous, dangerous; seductive," from PIE *leubh-ro-, suffixed form of root *sleubh- "to slip, slide."

lubricant (n.)

"material that can reduce friction in rubbing surfaces," 1828, probably from lubricant (adj.), or else from Latin lubricantem.