8 Wintry Words to Defrost Your Vocabulary
1892, agent noun from invigilate.
1550s, from Latin invigilatus, past participle of invigilare "watch over, be watchful, be devoted," from in- "in" (see in- (2)) + vigilare (see vigil). Especially in reference to student exams. Related: Invigilated; invigilating.