나무를 심다.

The phrase '나무를 심다' is composed of '나무' (namu), meaning 'tree', and '심다' (simda), meaning 'to plant'. **나무 (namu):** * **Old Korean:** The word for tree in Old Korean is not directly attested in its modern form, but related forms and concepts exist. * **Middle Korean:** In Middle Korean (roughly 10th to 16th centuries), the form was '남' (nam) or '남ㅎ' (namh), often appearing in compounds. The suffix '-우' (-u) was later added, possibly as a diminutive or a general noun suffix, leading to '나무'. * **Sino-Korean Influence:** While '나무' is an indigenous Korean word, Chinese characters related to trees (e.g., 木 'mok' for wood/tree) have also influenced the vocabulary, particularly in more formal or scientific contexts, but '나무' remains the primary everyday term. * **Hypothesized Proto-Korean/Altaic Roots:** Some linguists propose connections to Proto-Altaic roots related to plants or wood, though these are often debated and difficult to definitively prove due to the time depth. **심다 (simda):** * **Middle Korean:** The verb '심다' also has roots in Middle Korean, appearing as '심다' (simta) with a similar meaning of 'to plant' or 'to sow'. * **Semantic Expansion:** Over time, '심다' has retained its core meaning but can also be used metaphorically, such as '마음에 심다' (to plant in one's heart, meaning to engrave or impress). * **Related Verbs:** It shares semantic space with other verbs related to cultivation or placing, but '심다' specifically refers to putting seeds or plants into the ground. **Combination '나무를 심다':** * The combination is a straightforward direct object construction: '나무' (tree) is the object, marked by the object particle '를' (reul), and '심다' (to plant) is the verb. This structure is very common and transparent in Korean grammar. * The phrase literally means 'to plant a tree' and has been consistently used with this meaning throughout the modern Korean period. Its simplicity reflects a fundamental human activity of cultivation, making it a very stable and ancient lexical combination in the language.