Simply cloaking is a hiding procedure for the content of black hat seo. Cloaking is a concealment of content for search engine optimization. Based on the spider of various search engines that presents different content to the user
Cloaking is a search engine optimization (SEO) technique in which the content presented to the search engine spider is different from that presented to the user's browser. This is done by delivering content based on the IP addresses or the User-Agent HTTP header of the user requesting the page.
clocking is in general used in affiliate blogs to hide the affiliate link. So the affiliate sites will use it like domain.com/go/product. Such links are known as clocking. When a user opens that link it will redirect to the affiliate site.