The correct spelling of "wast trained" is actually "was trained." In IPA phonetic transcription, this would be spelled as /wəz treɪnd/. The mistake likely arose from a mishearing or misunderstanding of the spoken phrase. It's important to pay close attention to pronunciation and double-check spelling, as small errors can impact the clarity and credibility of one's writing.
The phrase "wast trained" does not have a specific etymology as it is not a commonly used phrase or word. However, "wast" can be a contraction of "was not" or "waste" depending on the context. "Trained" means to have been educated or skilled in a particular activity.