In high school, I bought a used copy of a similar book for 50 cents at a book fair: https://en.wikipedia.org/wiki/A_Dictionary_of_Slang_and_Unco...
It was fun to just thumb through it and find bizarre old phrases like "cat's pyjamas."
Cool to see an open and digitized version of something similar, especially something better than urbandictionary, which can be useful, but also has a lot of repeat entries and a stupid ability to downvote correct entries.