‘耳聪目明’ literally means ‘ears sharp, eyes bright’—a vivid four-character idiom describing someone with exceptionally keen hearing and sight, and by extension, mental alertness, clarity of thought, and quick comprehension. Each character contributes: 耳 (ear) and 目 (eye) are sensory organs, while 聪 (acute hearing) and 明 (clear vision/brightness) describe their heightened function. Together, they form a classical expression emphasizing holistic perceptual and cognitive acuity.

This phrase is commonly used to praise elders who remain mentally vigorous despite age, or to describe someone’s sharp presence during discussions, learning, or observation. It carries a positive, slightly formal or literary tone—often found in writing, speeches, or respectful compliments—not in casual slang. Though rooted in physical senses, its modern usage focuses almost entirely on mental agility and attentiveness.