Euphemisms often evolve over time into taboo words themselves, through a process described by W.V.O. Quine, and more recently dubbed "the euphemism treadmill" by Steven Pinker. This is the well-known linguistic process known as pejoration. When I had first heard of the concept I thought that it was a result peoples tendency to be offended by labels. I had heard of the Euphemism Treadmill occurring with the word Black being a euphemism for Colored which was originally a euphemism for Negro and so on.
But after seeing how there is an opposite trend, words that are purposefully offensive to becoming more mainstream( the Dysphemism Treadmill), my thoughts have changed. Our culture wants to use the offensive term so when a euphemism is created it is co-opted because it is simply the new negative term. If some grew up using Colored as an insult for Black or "African American" people then when the term black or "African American" is introduced you put it on as a mask to the word Colored. And you will use the euphemism to seem polite but in reality it has the same connotations as the original word. In some cases, the euphemism may be used mockingly and become dysphemisms.
And a word goes from being a dysphemism to being a more neutral word because we want to be able to use the negative or scandalous word. Then in order to seem polite we deny the words real meaning.Then as time goes on people learn the word with out its real meaning.
And example of the euphemism treadmill is that idiot, imbecile, and moron were once neutral terms for a person of toddler, preschool, and primary school mental ages, respectively. The word mentally retarded was pressed into service to replace Idiot, imbecile, and moron because negative connotations tend to crowd out neutral ones. Now that too is considered rude, used commonly as an insult. As a result, new terms like developmentally disabled, mentally challenged and special have replaced retarded. .In these cases, notions of profanity, obscenity and other words once called “offensive” are later described as “objectionable,” then “questionable,” and in some cases, they reach near or outright acceptability. One modern example is the word "sucks". "That sucks" began as American slang for "that is very unpleasant", and is shorthand for "that sucks cock", referring to fellatio; along with the exactly synonymous phrase "that blows", it developed over the late-20th century from being an extremely vulgar phrase to near-acceptability. Likewise, scumbag, which was originally a reference to a used condom, now is a fairly mild epithet.
The same may be said of the use of “screw,” often used as a dysphemism for sexual intercourse, is now in not such usages as “to screw up” (to make a major mistake).
Sometimes a term will go from being a euphemism to being a dysphemism and then go back to being a euphemism. “Queer” and “gay,” for example, both started as euphemisms for “homosexual,” and then got on the euphemism treadmill and became insults—but are now the preferred adjectives amongst the gay community themselves. Though This is often the result of intentional reappropriation campaigns.