The online version of Webster's 1828 is pretty good (third-party project because the work is in the public domain):

https://webstersdictionary1828.com/

To go the better route, here's a HN post about adding Webster's 1913 to the macOS dictionary app (the dictionary is very good):

https://news.ycombinator.com/item?id=29733648

If anyone is aware of a .dict file to add Webster's New International Dictionary, Second Edition (1942) to the MacOS Dictionary app, please post! That would be the holy grail for me.