the.com/impostor syndrome

means The persistent feeling that your achievements are undeserved or the result of luck, and that at any moment you'll be exposed as a fraud despite evidence of your competence.

from Coined in the late 1970s by psychologists Pauline Clance and Suzanne Imes, who originally called it the 'impostor phenomenon' while studying high-achieving women who, despite credentials and praise, privately believed they'd fooled everyone into overestimating them. 'Impostor' itself traces back through French to the Latin imponere — 'to impose' or 'deceive' — literally to put something false upon another. The irony is that the term was built to describe people deceiving no one but themselves.