愉

A phono-semantic compound consisting of:

心 (heart) — semantic component, indicating emotion or feeling; 兪 (yú) — phonetic component, providing the sound. The structure conveys a heart in a state of ease or comfort, leading to meanings like “pleasant” and “joyful.”
Semantic development: - emotional state of the heart; - ease and comfort; - pleasant feeling; - joyful and cheerful mood. Thus, 愉 represents gentle, harmonious happiness, rather than intense emotion.

유쾌 (愉快) — pleasant; cheerful

쾌유 (快愉) — recovery (originally implying a return to a pleasant state)

Often appears together with 快 (愉快), reinforcing the sense of pleasantness.

Compared to 喜 (joy), 愉 is softer and more relaxed in tone. Common in descriptions of mood, atmosphere, and emotional state. The character reflects an ideal of balanced and harmonious emotional well-being.
Related characters: 樂 — joy; pleasure

喜 — joy; delight

快 — pleasant; refreshing

悅 — delight; satisfaction

Among these, 愉 emphasizes calm, comfortable enjoyment, often without strong excitement.