The word "terrorist" itself can be a barrier rather than an aid to understanding. We should try to avoid the term, without attribution. [...] We should use words which specifically describe the perpetrator such as "bomber", "attacker", "gunmen", "kidnapper", "insurgent" or "militant."
George Orwell, As I Please, 2nd June 1944
Nearly all human beings feel that a thing becomes different if you call it by a different name. Thus when the Spanish civil war broke out the B.B.C. produced the name "Insurgents" for Franco's followers. This covered the fact that they were rebels while making the rebellion sound respectable.