擅自
shàn zì · HSK 7
without permission
🚫 擅 arbitrarily/take liberty + 自 self = acting on your own, no permission asked
擅 means to do something high-handedly or without authority; 自 means self or oneself. Together they mark an action taken on one's own initiative, without getting the go-ahead first.
自 — pictograph of a nose
自 originally depicted a human nose, shown frontally with the bridge and nostrils. Ancient Chinese pointed to their own nose to mean 'me,' so 自 shifted to mean 'self' or 'oneself.' A new character 鼻 was later created to carry the original 'nose' meaning.