根深蒂固
gēn shēn dì gù · HSK 7
deep-rooted (problem etc)
🌳 根 root + 深 deep + 蒂 stem + 固 firm = roots deep, stems firm
Four-character idiom built from two parallel pairs: 根深 (roots are deep) and 蒂固 (stems/bases are firm). Used for habits, beliefs, or problems too entrenched to easily remove.
根 — tree radical 木 + 艮 (phonetic)
根 is a semantic-phonetic compound. The left side 木 ('tree') gives the meaning, since the character originally referred to the roots of a tree. The right side 艮 supplies the sound. From 'tree root' it extended to mean 'root, base, foundation' in general.
深 — water radical 氵 + 罙 (phonetic, depth)
深 combines the water radical 氵 with 罙, which depicts a hand reaching into a cave or hollow. Originally it described deep water, then broadened to mean 'deep' in any sense — distance, color, or feeling. The 氵 gives the meaning, while 罙 hints at both sound and the idea of reaching far in.