啞おし

Used mainly in formal, medical, or historical contexts to refer to muteness or a mute person; rarely used in everyday conversation.

彼は啞のため言葉を話せない。
Kare wa oshi no tame kotoba o hanasenai.
He cannot speak because of his muteness.

啞の状態を改善する治療法が研究されている。
Oshi no jōtai o kaizen suru chiryōhō ga kenkyū sarete iru.
Treatments to improve the condition of muteness are being researched.

⚖️ Often confused with 唖 (a variant spelling); 啞 is the standard form in modern Japanese.