Keyword Stuffing is a black-hat activity that refers to the practice of attempting to manipulate the ranking of a website in the search results by over-optimising content to try and increase keyword density. In an attempt to do so, target keywords may be placed inappropriately on the web page and in places that don’t seem natural.
When webmasters tend to use the keyword stuffing strategy, users may find that the content doesn’t make sense, and in some cases, it doesn’t read properly. As the content is designed for the search engines and not the users themselves.
Including irrelevant keywords into your copy and attempting to keyword stuff is strictly against Google’s guidelines, doing so may result in your website being penalised, therefore, crippling the authority of your website.