A "mercenary army" means a group of soldiers who are paid to fight for a particular country, organization, or individual, rather than being part of an official military force of a country. Full definition
BB is leading his self - created mercenary army, Militaires Sans Frontières, through leafy Costa Rica at the behest of an undercover KGB agent who claims to be a professor at the «University of Peace». (theguardian.com)
Could the well armed mercenary army led by Vladimir Kulich be so truly pathetic (doesn't exactly give Danish mercenaries a good name)? (thecriticalcritics.com)
It features just one level — the Guantánamo Bay - inspired Camp Omega — and in it you play as Big Boss, a legendary soldier and the leader of nationless mercenary army Militaires Sans Frontières. (pcgamer.com)