ἑορτάζειν
From LSJ
τὸ δ' ἐξαίφνης τὸ ἐν ἀναισθήτῳ χρόνῳ διὰ μικρότητα ἐκστάν → suddenly refers to what has departed from its former condition in a time imperceptible because of its smallness
Greek > English (Woodhouse Verbs Reversed)
(see also ἑορτάζω): hold a celebration, keep festival, keep holiday