Doublespeak is language that deliberately distorts the truth, and sometimes reverses it completely. Doublespeak has been associated with "political language" and it is indeed widely used by politicians, government, the military and other centres of "authority".
When words lose their meaning, people lose their freedom.Confucius, Chinese Teacher 551-479 BC
Doublespeak is sometimes classed as a kind of euphemism. On these pages we treat doublespeak in its own category since the objective of doublespeak is to deceive, whereas the objective of euphemism is to soften.
I reminded [the soldiers] and their families that the war in Iraq is really about peace.President George W. Bush, April 2003
Doublespeak is language which pretends to communicate but doesn't. It is language which makes the bad seem good, the negative seem positive, the unpleasant seem attractive, or at least tolerable. It is language which avoids, shifts or denies responsibility; language which is at variance with its real or purported meaning. It is language which conceals or prevents thought.William Lutz
See examples of doublespeak here, with sample sentences and quizzes.