Doublespeak, Doubletalk, et cetera
(euphemisms, question-begging, declarifications, and cloudy vagueness sometimes designed to make lies sound truthful)
"The great enemy of clear language is insincerity. When there is a gap between one's real and ones' declared aims, one turns as it were instinctively to long words and exhausted idioms, like a cuttlefish squirting out ink."