brainiac

['brenɪæk]

brainiac (n.): "very smart person," 1982, U.S. slang, from brain (n.) + ending from ENIAC, etc. Brainiac also was the name of a comic book villain in the Superman series and a do-it-yourself computer building kit, both from the late 1950s, and the word may bear traces of either or both of these.