subaqueous
/ˌsʌbˈeɪkwɪəs/adjective
1- existing, formed, or taking place under water水下的, 水中的。
1.1
- figurative lacking in substance or strength〈喻〉空洞无物的; 无力的, 微弱的：
the light that filtered through the leaves was pale, subaqueous.
透过树叶的光线显得苍白、微弱。