What does brainiac mean?

brainiac meaning in Etymology Dictionary

"very smart individual," 1982, U.S. slang, from mind (n.) + ending from ENIAC, etc. Brainiac also ended up being title of a comic book villain into the Superman series and a do-it-yourself computer building system, both through the belated 1950s, and word may bear traces of either-or these two.

brainiac meaning in General Dictionary

someone who has excellent intellectual capability and creativity