Mercenary (noun)

1. A person who works for pay, especially in the military or security field and who is not motivated by loyalty or ideology.
2. A person who is mainly motivated by money or other material gain.

Origin:

From old french mercenaire, from latin mercenarius ("hired, mercenary"), from merces ("wages, pa.y")

Examples:

1. The company hired mercenaries to provide security for the oil fields.
2. He was a mercenary soldier, fighting for whoever would pay him.
3. The mercenaries were accused of war crimes.
4. The company was accused of using mercenaries to break the strike.
5. He was a mercenary businessman, only interested in making a profit.