Militarism, especially in contemporary use, has no single definition. It is not simply, as in Samuel Huntingon's work The Soldier and the State, the practice of civil-military relations. Rather, it refers to situations where the military is considered to have undue influence on national policy. If one accepts the maxim of Carl von Clausewitz that war is the extension of national politics by military means, one can observe a contradiction of the national politics is the will of the military.
Those opposed to military action, in any form, may use it as an epithet. It may apply to situations where the military, rather than civilians, govern, often having taken control of the government.
More subtle usages may avoid the specific term, but speak, as did Dwight D. Eisenhower, of a military-industrial complex with undue influence on national policymaking. Japanese militarism, before World War Two in the Pacific, can be defined operationally: of all the means that comprise grand strategy, only military methods remained as an alternative.
In states not generally described as militaristic, can be civilian control of the military, or the military can be part of a power balance, such as the traditional Party-Army-Organs of State Security in the Soviet Union.