Answer: dysphemism

AnswerCrossword Clue
DYSPHEMISMCalling a Jaguar XK a jalopy, say
dysphemismthe substitution of a harsh, disparaging, or unpleasant expression for a more neutral one.
dysphemismthe substitution of a disagreeable or offensive expression for an agreeable or inoffensive one, eg The Holocaust (the dysphemism chosen by Jewish historians to replace the Nazis' ghastly euphemism, The Final Solution)