Dunning–Kruger effect
Etymology
Named for social psychologists David Dunning and Justin Kruger, whose 1999 paper "Unskilled and Unaware of It" argued that incompetence hides itself because it removes the very yardstick needed to measure it. The popular version — a tidy graph with a "peak of stupidity" — oversimplifies the original finding, which was about weak metacognition, and some statisticians argue part of the effect is an artifact of how the data is measured. Still, the core observation about self-assessment blind spots holds up in ordinary life.
noun · /DUN-ing KROO-ger ih-FEKT/
The tendency for people with low ability in a domain to overestimate their competence, precisely because the skills needed to do well are the same ones needed to recognize doing poorly.
What it names
It explains why the least informed people in a debate are often the most confident, and why real expertise tends to arrive with more visible doubt.
Example
A month of reading forums convinced him he understood monetary policy better than economists — a near-perfect Dunning–Kruger effect.
Related idea
Impostor syndrome is the mirror image — competent people underrating themselves — whereas this names the overconfidence of the underskilled.