1 perspicacious 敏锐、有洞察力的

注释 Having or showing penetrating mental discernment; clear-sighted. 具有或展现出敏锐的心理洞察力；清晰的判断能力

例句

You are a perspicacious observer, Mr. Wang.

王昱珩先生，您是一位敏锐的洞察者。

2 perceptive 感觉灵敏；有洞察力；有理解能力

注释 Having or showing keenness of insight, understanding, or intuition. 具有或显示出敏锐的洞察力、理解力和直觉。

例句

Our victory depends very materially upon his perceptive power.

我方的胜利极大地仰仗着他的洞察能力。

3 discerning 有辨识力

注释 Showing good or outstanding judgment and understanding. 具有良好的或出众的判断力和理解力。

例句

Indeed, the growth of his business is proof of his skill at discerning what it is that consumers want to wear.

的确，他的生意越做越大，这便是他能敏锐察觉顾客喜欢穿什么的最好证明。

此外，还可以用sharp-eyed（目光敏锐、观察入微的）、quick detection（敏锐侦查能力）、rapid discernment（快速洞察力）来形容水哥的观察技能。