E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Dutch Uncle.
I will talk to you like a Dutch uncle. Will reprove you smartly. Uncle is the Latin notion of pat’ruus, “an uncle,” “severe guardian,” or “stern castigator.” Hence Horace, 3 Od. xii. 3, “Metuentes patruæ verbera linguæ” (dreading the castigations of an uncle’s tongue); and 2 Sat. iii. 88, “Ne sis patruus mihi” (Don’t come the uncle over me).
