1. 冲刷找矿法：hush-hush 极秘密的 | hushing 冲刷找矿法 | huskily 嘎声地

noun

1. a fricative sound (especially as an expression of disapproval)

e.g. the performers could not be heard over the hissing of the audience

Synonym: hisshissingfizzlesibilation