壻

Phono-semantic compound:

士 (“scholar, man”) — semantic element.

胥 (서로 서, phonetic) — phonetic element.

Thus the character denotes a male relative by marriage, i.e., a son-in-law.

壻 / 婿 (서) — son-in-law

女壻 / 女婿 (녀서) — son-in-law (lit. “daughter’s husband”)

東床婿 (동상서) — son-in-law, esp. one chosen for scholarly talent (“son-in-law on the eastern couch,” an allusion to Wang Xizhi)

婿 (U+5A7F) — formed with 女 (“woman”) instead of 士; this is the standard form used in modern Chinese and Japanese.

壻 is attested in older texts and occasionally in Korean usage.