brainy	intellectually clever or active
gifted	exceptionally talented or intelligent
intelligent	quick of mind, clever
knowledgeable	well informed, intelligent
outspoken	given to or involving plain speaking, frank in stating one's opinions
shrewd	showing astute powers of judgment, clever and judicious
smart	clever, ingenious, quick-witted
sophisticated	educated and refined
well-read	knowing a lot about different subjects
wise	having experience and knowledge and judiciously applying them
witty	showing verbal wit