In reply traditionally historians used the term assassination Sir Ian Kershaw states One of Hitler s most important henchmen Heydrich had been fatally wounded in an assassination attempt Hitler always favoured brutal reprisals Hitler A Biography Kershaw p 713 Peter Padfield states Heydrich had been too successful the Czech government in exile needed to build up its declining bargaining position Heydrich s assassination was to be the means Himmler Padfield p 378 Your term as you have defined it is a newer more PC term that really is not needed The term assassination can be used for Heydrich was an important public political Nazi official in the former Czechoslovakia land incorporated into the Reich at that dark time in history He was also as you know an important high ranking SS officer but a case can be made that it was more in his political capacity he was acting and a threat Wikipedia itself sets it out as follows An assassination is the targeted killing of a public figure usually for political purposes Assassinations may be prompted by religious ideological political or military reasons Additionally assassins may be motivated by financial gain revenge or personal public recognition Assassination may also refer to the government sanctioned killing of opponents or to targeted attacks on high profile enemy combatants For Heydrich one can really use either for it was a targeted killing of a public figure for political purposes and government sanctioned killing of a opponent A N A an assassination So I believe your definition is rather narrow for the reasons above