The phrase "wast mad about" is a colloquialism that means "you were very angry." The spelling of "wast" reflects an archaic form of the verb "to be" in the past tense, while "mad" is an adjective that describes the intensity of one's anger. The pronunciation is written phonetically as /wɑst mæd əˈbaʊt/. While this spelling and pronunciation are not commonly used today, they provide a glimpse into the evolution of the English language over time.