1. An unclear, imprecise, or poorly defined boundary or dividing line between two areas, concepts, or territories
There is a vague demarcation line between amateur and professional sports.
Existe uma linha de demarcação vaga entre desportos amadores e profissionais.
2. A border or limit that lacks clear definition or specific markers
The vague demarcation line between the two properties caused disputes among neighbors.
A linha de demarcação vaga entre as duas propriedades causou disputas entre vizinhos.