The Collaborative International Dictionary
Invigilating
invigilate \invigilate\ n. ([i^]n*v[i^]j"[i^]l*[=a]t) [imp. & p. p. Invigilated ([i^]n*v[i^]j"[i^]l*[=a]`t[e^]d); p. pr. & vb. n. Invigilating.] [L. invigilare to stay awake, to be vigilant.] To keep watch.
2. To keep watch over examination candidates to prevent cheating. [British]
Wiktionary
invigilating
vb. (present participle of invigilate English)