Wast
Wast is the archaic second-person singular past tense form of the English verb to be, used with the pronoun thou. In modern English, the equivalent expression is you were. Wast appears most often in historical texts, poetry, and literature from the Early Modern English period and earlier, when thou was still commonly used as the familiar second-person pronoun.
Linguistically, wast reflects the older conjugation system of English, where the verb to be possessed distinct
In contemporary writing, wast is rarely used outside of deliberate archaizing or quotations from older sources.
See also: to be, was, were, thou, archaic English, Early Modern English.