1. An indirect or passing reference to something that is ambiguous, vague, or difficult to understand
The author's unclear allusion to historical events confused many readers.
A alusão obscura do autor a eventos históricos confundiu muitos leitores.
2. A hint or suggestion that lacks clarity about its intended subject or meaning
Her unclear allusion to their past relationship left him wondering what she meant.
Sua alusão obscura ao relacionamento passado dele o deixou se perguntando o que ela quis dizer.