Keyword stuffing is known as an illegal search engine optimization technique that involves adding an excessive amount of keywords into the HTML or tags of a webpage to bring more traffic to a website.

Hi,

keyword stuffing is repeating same exact keyword so many times without having importance in the content to rank better in search engines, so we have to use LSI keywords to come out this problem.
Keyword stuffing will causes Google Penguin penalty.

it is known as bad technqiue..repeating keyword again and again