What is keyword cannibalization? keyword cannibalization happens when there are too many keywords that are identical or similar to each other spread across the entirety of your website. If enough of the pages throughout your website contains similar keywords, then search engines aren’t able to discern which content it should rank higher. It could even lower the rank of all the pages that share these keywords.
How many pages on your website rank for the same word? As you can imagine from the description above, if you have enough pages that have the same keywords, then you’d think that’d be good, but in reality, targeting a particular term over multiple pages can have an opposite effect.
In the end, it could hurt your SEO efforts. This is what’s called keyword cannibalization.
Aleh Barysevich has a column that can be found on Search Engine Journal that teaches us what we can do about keyword cannibalization.