un·dress / ˌənˈdres/ • v. [intr.] take off one's clothes: she undressed and climbed into bed I went into the bathroom to get undressed. ∎ [tr.] take the clothes off (someone else).• n. 1. the state of being naked or only partially clothed: women in various states of undress. 2. Mil. ordinary clothing or uniform, as opposed to that worn on ceremonial occasions.Compare with full dress.