Hi vausham - Welcome to the community! I'm not sure I understand what you're seeking. Can you clarify what you mean by "differ in word frequency?"
This seems too simple, but is it possible you just need a thesaurus? Surely, I'm misunderstanding the need you've expressed, but I will try to help if I can.https://www.merriam-webster.com/thesaurushttp://www.thesaurus.com/
I just google it whenever I need to . I type in synonym followed by the word I am interested in and click on the promising link.
Sometimes I look for antonyms in the same way.