His superiority complex made him overconfident.

Arrogance refers to an attitude of superiority manifested in an overt way, while a superiority complex is a psychological defense mechanism where an individual feels and acts as though they are superior to others to cover up feelings of inferiority. In essence, arrogance is a behavior, whereas a superiority complex is a psychological condition.

He has a superiority complex.

She displayed her superiority in the competition by finishing first with a clear lead over the other participants.

tell him to chill or evict him :)