薄

A phono-semantic compound:

艸 (초) — semantic component, indicating plants or layers

溥 (부) — phonetic component, supplying the sound (박 / bó), and suggesting spread thinly

The image implies plant matter spread out thin, which naturally yields the sense thin or slight.

Semantic development:

- physical thinness — small thickness

- insufficiency — lacking substance or strength

- emotional distance — coldness, lack of warmth

Common compounds:

박약 (薄弱) — weak; feeble

박정 (薄情) — cold-hearted; unfeeling

박서 (薄書) — thin book (literary)

박빙 (薄氷) — thin ice; narrow margin

박막 (薄膜) — thin film; membrane

Compared with 薄 vs 細 (thin/fine), 薄 emphasizes lack of depth or substance, not fineness.

Related characters (thinness & weakness):

薄 — thin; weak

厚 — thick; generous

輕 — light

弱 — weak

淺 — shallow

Among these, 薄 spans physical thinness and emotional or moral insufficiency.