1520s, "impairment of the normal action of the nervous system in bringing body parts or organs into action," from Latin paralysis, from Greek paralysis "paralysis, palsy," literally "loosening," from paralyein "disable, enfeeble," from para- "beside" (see para- (1)) + lyein "loosen, untie" (from PIE root *leu- "to loosen, divide, cut apart"). Figurative meaning "loss of energy, loss of the power of performing regular functions" is from 1813. Earlier form was paralysie (late 14c., see palsy). Old English equivalent was lyft adl (see left (adj.)) or crypelnes "crippleness."