“وَ” (wa)a joining word meaning “and.” It connects this word to what came before.Corpus grammarCONJ — prefixed conjunction wa (and).
“أَنذِرْ” (ʾaandhir)means “And warn” in this verse. It is a verb. an action or state word. Here it is verb pattern four, second person — masculine — singular.Corpus grammarV — second person masculine singular imperative verb.