This has gotten lost in all the false meanings. A chip on his shoulder comes from the days when there was a formal declaration for a fight, punch-up etc. When a person disagreed strongly with someone over a personal belief, they would place a chip of wood on their shoulder and dare the other to knock it off. Once the other person did this signaled the beginning of the fight and thus punches were thrown. Examples of this can be seen in old British movies circa 1930-1950's.

We use this idiom to say that someone has a deeply held feeling or conviction about something (whether it annoys them or that they won't listen to any other opinion about it) and thus if you disagree then they will vehemently challenge you.
He has a real chip on his shoulder about his size, I had a chip on my shoulder about immigrants until I moved to another country.
by Speakada Lingo September 21, 2015
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"Chip on his shoulder" commonly refers to someone who has a self-righteous feeling of inferiority or a grudge. An example would be someone always bringing up how they are or were disadvantaged in some way.
Person 1:"I was raised in a working class family with no luxuries"

Person 2:"But now you're a millionaire..."

Person 3:"Don't worry about him mate, he's just got a chip on his shoulder."
by ElectricFishy August 12, 2008
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A description given to someone (male or female), who has a sense of superiority (valid or not) due to either past successes or a personal belief that they are "better" than those around then.
Kobe Bryant sometimes carried a chip on his shoulder during his regular season games. But who could blame the guy, he outscored every man on the court in nearly every single game.

The college freshman had a chip on her shoulder because she was the star player on her high school softball team. She soon realized that every one of her new teammates, was also the star of their high school team. And she would have to earn the respect of her peers.
by Anthony Calvo July 20, 2017
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Comes from when people spent more time around animals specifically horses. It refers to when someone refuses to do what they are told because the person in charge is incompetent.
A horse was refusing to do what it was told so a veterinarian was called in. The veterinarian examined the horse and noticed a chip of flesh was removed from the front shoulder of the animals leg (chip on his shoulder). As it turned out when the owner was drunk he walked the horse into the side of the barn door. Now the horse refuses to obey.
by fudmitri November 24, 2011
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One who has something to prove.

The diversely sourced definitions of this phrase all have a common factor; it refers to someone whose behavior indicates that he/she has something to prove. Whether due to an inferiority complex, a strong passionate conviction for one's personal beliefs, a sense of being victimized or treated unfairly, or a resistance to heed advice from a more knowledgeable; one tends to display an air of hyped self-confidence and/or superiority or bravado.
"She's overly defensive because he's got a...
"See? I was right! I try to tell him; He should've listened to me! If it weren't for that...
"I think part of his drive for success and power can be attributed to that...

.....Chip on his shoulder."
by L!ghtBearer February 5, 2019
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