Knowitall
noun blending-slang
One who behaves in such a way as to present themselves as having knowledge, more specifically the correct knowledge, about all things.
Etymology : blending of the words "know" "it" and "all"
Source : Conversation: "I hate those classes where there is that one kid, the knowitall, that always raises their hand so that no one else ever gets to speak."
Last modified: 5 December 2011