House-train is a common term used to describe the process of training domestic animals, such as dogs and cats, to use a designated space for their bathroom needs instead of doing it anywhere inside the house. The antonyms for the term 'house-train' include untrained, unschooled, uneducated, uninstructed, and undisciplined. These words signify the lack of training or discipline in the said animal. When pets are not house-trained, they tend to be a nuisance and can cause damage to the house, furniture, and other items. Therefore, it is essential to spend ample time training them to use the designated space for their bathroom activities.