Arrogant, having an exaggerated perception of one's qualities.(adjective)
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Use "big-headed" in a sentence
"Helena Bonham Carter (the big-headed Red Queen – literally) has some of the best one-liners in the film, but it feels like even she could have used a couple more."
"On the plus side, there are lots of pictures of cute, big-headed characters throughout."
"His big-headed characters are close enough to be parodies but with their own motivations."