This study reviews and classifies the most common uses of the terms "enemy" and "enmity" within the context of traditional philosophical discourse. In order to contribute to a structured understanding of these concepts, we proceed in two steps. We first explore the auxiliary (or non-technical) uses of the terms, which we distinguish from each other according to their axiological connotations. In a second part, we review the technical uses of the concepts known to philosophy of law. Here, we distinguish between two different approaches to the concept, one of which defines it through qualitative criteria, and a second approach that uses the term as a quantifier (of intensity, strength, etc.)