Knock (someone) down a notch (or two) verb phrase
To humble one; to damage someone's ego or pride
This newcommer is very arrogant. Let me knock him down a notch.
Losing his job knocked him down a notch.
His ego was knocked down a notch or two.
If one is brought down a notch (or two), they are reduced their pride or ego.
To humiliate someone, or show someone that they are not as important as they think.
To keep reminding someone of their failure or mistake.
To make one become realistic, especially for one often makes a boast
The verb "knock" must be conjugated according to its tense.
The origin of this phrase is not clear.