The word inexcusable means something that cannot be justified or explained away as an excuse. It is an adjective used to describe a mistake, action, or behavior that is considered to be unforgivable or unpardonable due to its severity or the harm it causes. The term implies a lack of care, thoughtlessness, or neglect on behalf of the person who committed the act, and suggests that there is no valid reason for their actions. In other words, an inexcusable action is one that goes beyond what can be forgiven or excused due to its serious nature or consequences.