Auld-Farrant

Esp. of a child or young adult: having the manners, temperament, or wisdom of an older person; characteristic of such a person; (sometimes more specifically) wise, prudent, shrewd. Now rare.
“auld-farrant, adj.” OED Online, Oxford University Press, June 2017, www.oed.com/view/Entry/57101179. Accessed 11 October 2017.