REH definitely had a good vocabulary. There are so many unique words in his poetry. I especially enjoy the archaic ones because they often have different meanings today. For instance, "bully" in the early 1900's meant a good chap--totally different from today's definition. What's even more amazing to me is that he knew the vernacular of whatever genre he was writing in: hobos, sailors, cowboys, boxers, etc.
Coondogbo: Since REH was a great fan of Shakespeare's, he probably used a great deal of those words in his poetry and prose. The Howard Bookshelf lists several entries for Shakespeare, including this one which says according to: Tevis Clyde Smith, "Report on a Writing Man": "He [REH] was equally at home in discussing Macbeth and Jack Harkaway."
For the rest the info about REH and Shakespeare, here is the bookshelf link: http://web.archive.o...bookshelf_s.htm