Keyword stuffing is the practice of using too many keywords or irrelevant keywords on your web page, in an attempt to manipulate your ranking and visibility on search engines. Keyword cannibalization is the practice of using the same or similar keywords on multiple web pages, in a way that confuses and competes with each other on search engines. Both practices can harm your SEO and user experience, and should be avoided. To avoid keyword stuffing and cannibalization, you should use keywords sparingly and relevantly on your web page, and use different and unique keywords for different web pages, based on the user intent and content of each page.