Soldiers who offers their services for money, irrespective of the nationality of the army in question.
Mercenaries in the Egyptian army
Jer 46:20-21 These mercenaries were drawn from Cush to the south of Egypt, Put to the west of Egypt and Lydia in north Africa.
Mercenaries in the Ammonite armySee also 2Sa 10:6 pp 1Ch 19:7
Mercenaries hired by Jehoiada the priest
Mercenaries in the army of Judah
Fear of mercenary attack