敏锐 (mǐn ruì) describes keen, sharp senses (smell, sight, hearing) or mental insight (market vision, questions). It differs from 敏感 (mǐn gǎn, HSK5), which means 'sensitive' to stimuli or emotions, often with a nuance of being easily affected or touchy. For physical sharpness of a blade, use 锋利 (fēng lì) or 尖 (jiān); for piercing sound or pointed criticism, use 尖锐 (jiān ruì).