To fail a test, class, or other requirement due to poor performance.
Likely from German 'flunks' or related to dialectal 'flunk' meaning 'to fail,' though the exact origin is debated. The term became common in American English in the 1800s as university slang for academic failure.
Some of history's most successful people famously flunked important tests and exams—Thomas Edison was considered a poor student, and Einstein struggled in school—which suggests that standardized testing measures a very specific type of thinking rather than actual intelligence or potential. The word 'flunk' is so American that most other English-speaking countries use 'fail' instead, making it a perfect example of how slang words become locked into regional identity.
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