1. A subject or theme that lacks clear boundaries, specific parameters, or explicit definition
The meeting became unproductive because the undefined topic led to scattered discussions.
A reunião se tornou improdutiva porque o tópico indefinido levou a discussões desorganizadas.
2. In academic or professional contexts, a subject matter that has not been clearly established or delimited
The research proposal was rejected due to its undefined topic.
A proposta de pesquisa foi rejeitada devido ao seu tópico indefinido.