Keyword stuffing

The practice of padding website content with keywords in an attempt to game search engines for higher rank on the SERPs. Often, this does not read like natural language, and is becoming less effective as search engines grow more sophisticated with regards to language. An example of keyword stuffing would be “Shop for moisture-wicking athletic socks at our moisture-wicking athletic socks store. Consult with our moisture-wicking athletic socks experts to get your moisture-wicking athletic socks!”

This is one of the tactics of black hat SEO, and because it does not read naturally, may be considered spam and be penalized by Google.