笃（du）
Name meaning
笃 (du) means sincere, genuine or (of an illness) serious.
Practical naming use
Use 笃 (du) when the name should suggest sincere, genuine. Keep the full two-character name natural, readable and balanced for everyday use.
Pairing guide
Pair 笃 (du) with characters such as 安 (An) for a steadier frame, 文 (Wen) for a cultured register, 清 (Qing) for clarity or 宁 (Ning) for calm. Let the second character clarify the intended register rather than doubling an already strong image.