自愿
zìyuàn · HSK 5
voluntary
🙋 自 = self + 愿 = wish/willing → self-willing = voluntary
自 means self (the same 自 as in 自己 'oneself'), and 愿 means wish or willingness. Together 自愿 literally reads as self-wishing — doing something of your own will, i.e. voluntarily.
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.
愿 — 原 (source) + 心 (heart)
A semantic-phonetic compound. The heart radical 心 carries the meaning of inner feeling or wish, while 原 (yuán, 'source/plain') supplies the sound. Together they depict a wish welling up from the heart, giving the senses 'to wish, to be willing'.