Militarism or militarist ideology is a view on society. It says society should be like the military. This means that society should follow concepts that can be found in the culture, system and people of the military. People that say militarism is good are called militarists.
Most important to militarists is discipline. Discipline means to follow a set of rules. It also means training that follows such rules. A strong military is good for discipline. There are many areas where moral goals and the culture of the military can be applied. Most notable are private business, government, education and entertainment.
Militarism is related to militarization, and militarist countries often have a strong military. Thus Sparta in Ancient Greece, and Prussia in the 19th century were militarist and had more powerful armies than other states their size. North Korea is a good example in modern times. In militarist states the military either run the government, or greatly influence it. Often the head of state is a military person, though that does not always mean the society is militarised.