I studied a reasonable amount of Shakespeare as part of my university English and Drama studies (Class of 2002). While I had a pretty damn good scholar running

I studied a reasonable amount of Shakespeare as part of my university English and Drama studies (Class of 2002). While I had a pretty damn good scholar running those courses, I didn't think there was anything unusual in the fact that he always described these as "words or phrases that were first written down by Shakespeare" rather than "invented by". Particularly when it comes to slang, words/phrases are often written down at some distance after they become commonly spoken. Hopefully the digitisation of additional early modern and medieval works helps with etymology - always frustrating to search for something and get six competing theories, all of which seem equally specious.