invigilate (v.) Look up invigilate at Dictionary.com
"to watch diligently" (archaic), 1550s, from Latin invigilatus, past participle of invigilare "watch over, be watchful, be devoted," from in- "in" (from PIE root *en "in") + vigilare "to watch, keep awake, not sleep" (see vigil). In late 19c. especially in reference to student exams. Related: Invigilated; invigilating.