A discourse community is a group that shares language usage including its traits. As a discourse community, military organizations present unique language forms of their own. In this paper, we explain this particulare linguistic phenomenon and the reason that members of the military use `malipnida` frequently. In other words, this paper aims to present research on the time, in any situation, with any intention for usage, that `malipnida` is selected. Analysis of the research data shows that semantic functions of `malipnida` can be largely categorized into five areas. As a polite expression, `malipnida` is relate to socio-cultural traits of military society closely, and it is used to avoid threats to social standing of upper-class members. In most cases, they realize these intentions through haeyoche(해요체) but in the military they implicitly restrict the use of these expressions. By the way, use of `malipnida` in the military is undergoing a change because of the effect of the policy responses for the suppression its use. Members of the military choose various expressions in the place of `malipnida` to comunnnicate politeness in a variety of ways.