prevent (v.) Look up prevent at Dictionary.com
early 15c., "act in anticipation of," from Latin praeventus, past participle of praevenire "come before, anticipate, hinder," in Late Latin also "to prevent," from prae "before" (see pre-) + venire "to come," from a suffixed form of PIE root *gwā- "to come" (see come). Originally literal; sense of "anticipate to hinder" was in Latin, but not recorded in English until 1540s.