Here are some words that drive me crazy, some are neo-logisms, some words which once had perfectly fine, even noble, meanings but are now being twisted and distorted into something ugly.
Pro-active--this is a non-sensical word, which doesn't mean what people think it means. It is used to indicate a policy or practice that is not reactive. However, pro- is not an antonym for re-. "Pro" means to support or favor. When someone or some organization says they will be "pro-active," it is usually an expression of vague intention.
Militant--has become the state of art to describe an irregular fighter for terrorist organizations like Hezbollah or Hamas. It used to mean a grass roots activist in a left wing political party. A New Yorker article in the late 1940s described Leon Birkhead's League for Democracy as "militant" defenders of civil liberties.
Dissident--a while back, NPR described the breakaway violence-prone splinter of the Irish Republican Army as "dissidents." The term that once described brave men and women like Andrei Sakharov who spoke and acted for democratic rights against the Soviet dictatorship is now being applied to thugs who have more in common with the Gulag masters and the KGB than with real dissidents. Apparently, the term "dissident" is used in Irish political discourse in this manner., but that is no excuse for the journalists of NPR to adopt it.