Army
A soldier may be a volunteer (someone who joins something because they want to), or he may be forced by the government to join the army.  Forcing men to join the army is called conscription or draft. Voluntary armies tend to be small by numbers, but high in confidence and quality. Drafted armies are large, but often lacking in confidence and in quality: it may be very difficult to force someone to risk his life against his will. Sometimes an army is made up from mercenaries, who fight just for pay and have little loyalty to the country which they serve.