A euphemism /ˈjufəˌmɪzəm/ is a generally innocuous word or expression used in place of one that may be found offensive or suggest something unpleasant. Some euphemisms are intended to amuse; while others use bland, inoffensive terms for things the user wishes to downplay. Euphemisms are used to refer to taboo topics (such as disability, sex, excretion, and death) in a polite way, or to mask profanity.
Euphemism comes from the Greek word εὐφημία (euphemia), meaning "the use of words of good omen", which in turn is derived from the Greek root-words eû (εὖ), "good, well" and phḗmē (φήμη) "prophetic speech; rumour, talk". Etymologically, the eupheme is the opposite of the blaspheme "evil-speaking". The term euphemism itself was used as a euphemism by the ancient Greeks, meaning "to keep a holy silence" (speaking well by not speaking at all).
Euphemism use has a large range from the merely innocent to evading responsibility for war crimes. For instance, one reason for the comparative scarcity of written evidence documenting the exterminations at Auschwitz (at least given the scale) is "directives for the extermination process obscured in bureaucratic euphemisms".
The euphemism affirmative action meaning a preference for minorities or the historically disadvantaged usually in employment or academic admissions (also called reverse discrimination, or in the UK positive discrimination) is an example of a well-intentioned circumlocution to disguise intentional bias that might be legally prohibited, or otherwise unpalatable.