What is spam indexing: Spam indexing is the use of black hat techniques to rank the websites higher. It includes keyword stuffing, meta-tag stuffing, doorway pages etc.
Spam-Indexing is also known as Spamdexing. Spamdexing can include activities such as keyword stuffing, link spamming, duplication of copyrighted content. The spam indexing is an method modifying the html pages against the rules increase the chance of being place closed to beginning of search results main purpose of this try to get good rank in the search engine.