Unobservable
a. 难以察觉的；注意不到的；不可见的
✅ 同义词
🗣️ 情景例句
Still waters run deep.
冰冻三尺非一日之寒。
Congratulation!
恭喜！
Duck your head as you go through the door there.
经过那儿的门时，请将头放低。