White hat is a term used to describe “good” practices. Somone who does white hat SEO does not “cheat” or break search engine guidelines. White hat SEOs generally don’t take large risks by using tactics that are in gray areas because they want to avoid damaging SEO efforts. White hat SEO takes time but is more stable and dependable than black hat SEO. White hat results tend to last a long time.
Black hat is a term used to describe “bad” SEO practices in which search engine guidelines are not heeded. These could include spammy link building, private blog networks, hidden text, keyword stuffing, etc. Black hat SEO has been known to work and bring about quick results but they are short lived and often result in sites being penalized or deindexed from search engines completely.