1. A boundary, limit, or point of transition that is unclear, vague, or imprecisely specified, making it difficult to determine exactly when a condition begins or ends
The diagnosis of the disease relies on an ill-defined threshold for abnormal protein levels in the blood.
O diagnóstico da doença depende de um limiar mal definido para níveis anormais de proteína no sangue.
2. In technical or scientific contexts, a parameter or criterion that lacks precise definition or measurable specifications
The committee struggled with the ill-defined threshold for what constitutes acceptable performance.
A comissão teve dificuldades com o limiar mal definido do que constitui desempenho aceitável.