undertone

柯林斯词典

1. N-COUNT If you say something in an undertone, you say it very quietly. 低声['in' N]
"What d'you think?" she asked in an undertone. “你觉得呢？”她低声问。
2. N-COUNT If something has undertones of a particular kind, it suggests ideas or attitudes of this kind without expressing them directly. 隐含意[with supp]
...a witty, racy story with surprisingly serious undertones. ...一个诙谐活泼却有十分严肃的隐含意的故事。