[T]he Cognitive bias whereby people with low ability at a task overestimate their ability. Some researchers also include in their definition the opposite effect for high performers: their tendency to underestimate their skills.
Bibliography
“DunningKruger Effect.” 2022. Wikipedia, February. https://en.wikipedia.org/w/index.php?title=Dunning%E2%80%93Kruger_effect&oldid=1070028100.