HSK10+
sōu
whizzing sound
Phonosemantic compound. 口 represents the meaning and 叟 represents the sound.
口 Meaning component
kǒu
mouth
叟 Sound component
sǒu
old man
嗖
whizzing sound; (onom.) whooshing; swishing; rustle of skirts
swishing
嗖嗖
Make Me a Hanzi
Unicode
Dong Chinese
CC-CEDICT
SUBTLEX-CH
MTSU Chinese text computing