1.) A
knucklehead or idiot who's ignorant of the world around them. They lack
self awareness and are oblivious to what they say and their own actions.
2.) A blind
chauvinist that displays uncritical loyalty and enthusiasm towards a team, organization, leader, band, institution, etc in spite of their obvious faults and shortcomings. Usually belligerent to criticism no matter how constructive or benign it is to their entity they blindly and uncritically support.
3.) People who never learn from their mistakes or never learn period. See definition #1.
I'm no longer friends with him because he's such a homer. I didn't like his attitude nor could I
tolerate his ignorance and
lack of respect for others. He'll never learn from his own action nor
see the light.