心眼 (xīn yǎn) literally means 'heart + eye', but it is an abstract noun covering several related concepts. It can refer to one's inner thoughts and intentions, often with a sense of consideration or thoughtfulness toward others (e.g., 没心眼 means 'naive, without ulterior motives'). It also means cleverness or cunning — someone with 有心眼 is shrewd, possibly scheming. Additionally, in phrases like 心眼小 it describes narrow-mindedness or lack of tolerance. Context is key to picking the right sense.