落

It is a phono-semantic compound, formed from:

艸 (“grass, plants”) as the semantic element;

洛 (rak/nak, “river name”) as the phonetic element.

Because of the 艸 radical, its earliest meaning was specifically “leaves falling from plants.”

According to the Shuowen Jiezi, “When grass leaves fall it is called 零 (령), when tree leaves fall it is called 落.” From this botanical sense, the character extended to the general ideas of falling, decline, and ruin. Over time, it also developed minor senses of “to accomplish” and “village/settlement.”

In Korean, 락/낙 (落) appears in many compounds, most often with connotations of falling, decline, or being left behind:

낙엽 (落葉) – fallen leaves

낙후 (落後) – falling behind, backwardness

타락 (墮落) – moral corruption, depravity

몰락 (沒落) – downfall, ruin

낙오 (落伍) – falling out, being left behind

부락 (部落) – village, settlement, tribe

While often negative, some compounds are neutral or even positive, such as 정착 (定落, to settle) or 낙원 (樂園, paradise) where a different 락/낙 is homophonous.