Superlative form of dreary; the most gloomy, dismal, or joyless.
From dreary + -est (superlative suffix from Old English -est). This is the most extreme form, comparing something to all other possible instances of dreariness.
Superlatives like 'dreariest' are fascinating neurologically—using extremes ('the worst,' 'the best') actually primes your brain to remember information better, which is why advertisements love superlatives even though they're often exaggerated.
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