What do you call somebody that does something for someone else for money or other personal gain and not because they want to?
For example, when someone votes for a candidate in an election because they get paid to do so, and not because that's the candidate they want.
He only voted for the candidate because he was paid to do so. He's just a ________.
A mercenary :
- A person who works merely for money or other material reward; a hireling. In later use (probably influenced also by sense A. 2): a person whose actions are motivated primarily by personal gain, often at the expense of ethics.
The context does not have to be military. The OED gives the first of its meanings as non-military and quotes the following as an example :
1998 Mirror (Nexis) 18 Dec. 49 When Everton came in for me two seasons ago, West Ham were in relegation trouble. If I'd been a real mercenary, I'd have cleared off and left them to it.
He only voted for the candidate because he was paid to do so. He's just an unscrupulous person/man.
Dictionary.com provides the perfect description and meaning of this adjective
unscrupulous
Unscrupulous, unprincipled refer to lack of moral standards or conscience to guide one's conduct. The unscrupulous person is without scruples of conscience, and disregards, or has contempt for, laws of right or justice with which he or she is perfectly well acquainted, and which should restrain his or her actions: unscrupulous in methods of making money, in taking advantage of the unfortunate.The unprincipled person is without moral principles or ethical standards in his or her conduct or actions: an unprincipled rogue; unprincipled conduct.
If the OP is looking for a single noun, rogue, would be appropriate but it does imply that the person is generally dishonest and untrustworthy. Alternatively, an opportunist, is a single word and a noun.
Opportunist (noun)
1. a person who practices opportunism, or the policy of adapting actions, decisions, etc., to effectiveness regardless of the sacrifice of ethical principles:
