Mercenary (Mer-cen-ar-y): Adjective (of a person or their [sic] behavior): Primarily concerned with making money at the expense of ethics; Noun: A professional soldier hired to serve in a foreign army; Synonyms: adjective venal; noun hireling soldier of fortune
Assassin (As-sas-sin): Noun 1. A murderer of an important person in a surprise attack for political or religious reasons; 2. A member of a branch of Ismaili Muslims (1094-1256) renowned as violent military fanatics; Synonyms: murderer- killer- slayer-cutthroat
—The Merriam-Webster Dictionary
In his insightful memoir We Meant Well, Peter Van Buren, who had served as a State Department official in Iraq during the Bush administration, described the various “tribes” he encountered at his FOB (Forward Operating Base), including the military contractors, many of whom worked for the by-then-notorious Blackwater private military/security firm, or one of its many iterations:
Most were Americans, with a few exotic Brits and shady South Africans thrown in. . . . Not to their face, most people called these guys mercs, not contractors, in that they carried weapons on behalf of the U.S. government, sometimes shot at Iraqis, but were not soldiers. This is what the military would look like...