Is there a software library for an English language dictionary or word list?

I’m pretty sure it’s easy to find an English dictionary file as a CSV. Of course you’d have to write the code to pull it into a list and then run operations on that list. With about 200k items, that actually should be reasonably quick to do.

I once wrote a script that imported macOS’s built-in dictionary and then iterated through it to find all of the palindromes and didn’t recall it taking very long to run.

I found the library nltk for Python for natural language processing and found a Web site that told how to load the dictionary that the library uses. I was curious to find the longest word with no repeating letters. The best I could do on my own was the 13 letter word unproblematic. There was no noticeable delay when I ran the program. It returned the 15 letter word dermatoglyphics, which is the study of the ridges of fingers and toes, which I am guessing are fingerprints and toe-prints.