A.T. Robertson Commentary Luke 24:31

"And their eyes were opened, and they knew him; and he vanished out of their sight." — Luke 24:31 (ASV)

Were opened (διηνοιχθησαν). Ingressive first aorist passive indicative of διανοιγω.

Knew (επεγνωσαν). Effective first aorist active indicative fully recognized him. Same word in verse 16.

Vanished (αφαντος εγενετο). Became invisible or unmanifested. Αφαντος from α privative and φαινομα, to appear. Old word, only here in the N.T.