1To become weaker or thinner in concentration, intensity, or clarity; used intransitively for things like taste, color, or effects.
時間が経つにつれてスープの味が薄まった。
As time passed, the soup's flavor became weaker.
冬の間に色が薄まって、布が少し色あせた。
Over the winter the color faded and the fabric became slightly discolored.
薬の効果は時間とともに薄まることがある。
The effect of a medicine can weaken over time.