Erudite

er·u·dite /ˈɛryʊˌdaɪt, ˈɛrʊ-/ Pronunciation Key - Show Spelled Pronunciation[er-yoo-dahyt, er-oo-] –adjective

characterized by great knowledge; learned or scholarly

A history lesson?
One might like to be erudite but hesitate to be rude. This preference is because of the etymological relationship between erudite and rude. Erudite comes from the Latin adjective ērudītus which means "well-instructed, learned," and from the verb ērudīre, "to educate, train." The Prefix comes from the Latin root ex-, "out, out of," and the adjective rudis, "untaught, untrained," the source of our word rude. The English word erudite was first recorded in a work possibly written before 1425 with the meaning "instructed, learned." But the Erudite meaning "learned" is supposed to have come from a rare exception in sarcastic use during the latter part of the 19th century. The word now seems to have been restored to favor.

I would like to thank Jon Ostenson for my "root master" skills and Wikipedia for some insights.