Would you say that deprecate, disdain (as a verb), and denounce are synonyms?

These I found at Keyword: Thesaurus... an excellent help in checking synonyms and antonyms.
I would agree that those are synonyms

Synonyms bad-mouth, belittle, cry down, deprecate, depreciate, diminish, discount, disparage, minimize, put down, write off
Related words abuse, scold; disapprove (of), dislike; censure, condemn, criticize, denounce, reprehend, reprobate; asperse, defame, malign, slander, traduce, vilify; discredit, disgrace

Yes, deprecate, disdain (as a verb), and denounce can be considered synonyms. While there are various ways to determine if words are synonyms, one helpful tool is a thesaurus. In this case, the Keyword: Thesaurus was used to find the synonyms and related words for the word in question.

According to the Keyword: Thesaurus, some synonyms for deprecate include belittle, cry down, depreciate, diminish, discount, disparage, minimize, put down, and write off. Disdain, used as a verb, can also have similar meanings to deprecate. Other related words that have a similar connotation include abuse, scold, disapprove of, dislike, censure, condemn, criticize, denounce, reprehend, reprobate, asperse, defame, malign, slander, traduce, vilify, discredit, and disgrace.

By using a thesaurus or similar resources, it becomes easier to find synonyms and related words, allowing for a better understanding of the similar meanings and nuances of different words.