Black Hat SEO does not Follow the Guide Line of search engine.

I think that many people know about the Black Hat SEO means use techniques

If you try to use many keyword on tour content then its called black hat SEO or keyword stuffing.
To avoid keyword stuffing maintain keyword density below 3%.
to check keyword density when writing post, use Yoast Wordpress SEO plugins.
Yoast WordPress SEO settings guide

black hat SEO is a type of SEO which violet the policy of search engine. never try to black hat SEO.

Black hat seo does not follow the guide line of search engine.

Big NO NO for me.

In search engine optimization (SEO) terminology, black hat SEO refers to the use of aggressive SEO strategies, techniques and tactics that focus only on search engines and not a human audience, and usually does not obey search engines guidelines.