夫子

Classically, 夫子 was the highest respectful address for a learned man — most famously 孔夫子 (Kǒng Fūzǐ, Master Kong = Confucius), from which Western 'Confucius' is Latinized. By extension 孟夫子 = Mencius, 朱夫子 = Zhu Xi. Hong Kong's beloved comic 《老夫子》 (Old Master Q) keeps the term in pop-culture circulation today.

In modern speech 夫子 alone is archaic. 老夫子 (lǎo fūzǐ) is used jokingly for someone bookish and out-of-touch. Also note: 大夫 reads dàifu (doctor), not fūzǐ — different word.