“وَ” (wa)a joining word meaning “and.” It connects this word to what came before.Corpus grammarCONJ — prefixed conjunction wa (and).
“خَسَفَ” (khasafa)means “And becomes dark” in this verse. It is a verb. an action or state word. Here it is perfect verb, third person — masculine — singular.Corpus grammarV — third person masculine singular perfect verb.