1. A border, limit, or dividing line that is not clearly defined or precisely marked; an indistinct or fuzzy demarcation between two areas, concepts, or states
The vague boundary between art and entertainment has always been a subject of debate.
A fronteira vaga entre arte e entretenimento sempre foi motivo de debate.
2. In formal contexts, a limit or edge that lacks clear definition in mathematics, geography, or philosophy
The vague boundary of the forest made it difficult to determine where the protected land ended.
A fronteira vaga da floresta dificultava determinar onde terminava a terra protegida.