1520s, "to persuade a vassal, etc., to desert his allegiance or service," from Latin seducere "lead away, lead aside or astray," from se- "aside, away" (see se-) + ducere "to lead" (from PIE root *deuk- "to lead"). The sexual sense, now the prevailing one, is attested from 1550s (it apparently was not in Latin), originally specifically "entice (a woman) to a surrender of chastity." Related: Seduced; seducing.
Caxton used seduisen (late 15c.), from Old French suduire "to corrupt, seduce" (Modern French séduire "seduce"), from Latin subducere "draw away, withdraw, remove" (see subduce).