n a subdued emotional quality underlying an utterance; implicit meaning
n a current below the surface of a fluid
n. 暗流, 潜流, 电流不足
1. There is an undercurrent of tension in the room during the meeting.
会议期间，房间里弥漫着一股紧张的气氛。
2. The river has a strong undercurrent that can be dangerous for swimmers.
这条河流有强烈的暗流，对游泳者来说很危险。
3. His smile hid an undercurrent of sadness that few people noticed.
他的微笑掩盖了一种少有人察觉的悲伤。