Late 17th century; earliest use found in White Kennett (1660–1728), historian and bishop of Peterborough. From either proverbial or proverbial + -izing.
proverbializing2
/prəˈvəːbɪəlʌɪzɪŋ/
adjective
That makes or utters proverbs.
Origin
Late 17th century. From proverbial + -izing. Cf later proverbialize, proverbializing.