Definition: Someone you'd categorize as being corny or trite
Synonym: dork, loser
Lyric: "I warned y'all cornballs, I hush puppies/The swans in the pond called my duck ugly" -- Lupe Fiasco, 'I Gotcha'
Before he became a 'Superstar,' Lupe could have easily been mistaken for the astute -- but definitely not cool -- boy next door. I'm sure anyone who called the rapper a cornball is eating his words as we speak.