Cocksucker

The word cocksucker is a form of vulgar slang, and is considered by some, along with motherfucker, to be one of the strongest insults in the English language.

The term refers to the practice of fellatio, but is often used as an insult rather than referring to someone who performs the act. However, it is also used as an anti-gay slur.

Some people, however, consider the term "cocksmoker" even more offensive, especially when a hardsounding, almost German accent is used for the "cock" part of the word. This insult was popularized by the movie "Clerks," after which some people incorporated this word into their everyday language.