This video on Catholic “Just Defense” theory has one explanation and definition of militarism. It also gives a decent overview of Catholic Just War theory: where it came from and what it says. It has six parts but is only about 30 minutes long in total:

“Those who hold this position or set of assumptions believe that violence and war are not evil in themselves and can be effective means to bring about positive result. Violence and war can be used to right wrongs, to protect the innocent, and to restore order and peace. Indeed the militarist position maintains that not only is killing for the right reasons justifiable, it is also honorable and noble. Human beings are violent by nature, the militarist position reasons, and so good people must not avoid violence. It is imperative that the good guys outgun the bad guys. Thus, legitimate violence, the violence of the good guys, is a sign of courage and virtue, and the rejection of such violence is a sign of cowardice, or vice. Violence is glorified, and the good guys who employ legitimate, sanctioned violence are heroes.”