The dictionary in the version of LO Writer that I am using is very sad. Many, many ordinary words are not there! So, if LO knows of a good download, please let me know.
Umm, folks here aren’t “LO”. We are just users, some of us just like you.
Anyway, regarding your question, have you looked at the LibreOffice extension library? I have installed the Oxford English Dictionary (OED) v1.0.3 but that is probably not what you are looking for, it being British English rather than American English. There are others.
Once you have downloaded an extension and saved it in a convenient place, use the Extension Manager (menu Tools → Extension Manager) to install it in LibreOffice. Hope this helps.
Your question is not related to AskLO site dysfunction. Please use retag to remove meta.
Sorry, I do not understand what ‘tags’ are, nor how to use them. I just kept adding one until it let me ask my question!
[Retagged.]