The spelling of "wast negligent" may seem unusual but it follows standard pronunciation rules in English. The "wast" part is an archaic form of "was" that was commonly used in Shakespearean English. The "negligent" part is spelled using IPA phonetic transcription as /ˈnɛɡlɪdʒənt/, with the emphasis on the second syllable. The word means failing to take proper care or being careless. Overall, the spelling of "wast negligent" can be traced back to its historical roots and is a valid variant of the phrase "was negligent."
The phrase "wast negligent" appears to be a combination of Old English and Middle English words.
The word "wast" is the second-person singular form of the verb "to be" in Old English. It derives from the Old English word "wesan" which means "to be". In Middle English, the verb "wast" was often used when addressing someone directly.
The word "negligent" comes from the Latin word "negligentia", which means "carelessness" or "neglect". It has been borrowed into English from Latin.