bighead

noun3

1. •
   (informal) A person with an inflated opinion of themselves; a conceited or arrogant person.

   • He is such a bighead and so lazy that I don't know how far he will go. He can read and write English a little bit and he thinks that is enough for him to know. — 1997
2. •
   Any of several species of fish having a large head.
3. •
   Any of several animal diseases that cause swelling of the head.