The superlative form of guilty, meaning most responsible for doing something wrong or most likely to have committed a wrongdoing.
From guilty + -est (superlative suffix). Guilty comes from Old English gylt (crime, sin), possibly from Old Norse gilt. The superlative form developed in English to compare degrees of culpability.
The word guilty is actually quite mysterious in origin—linguists aren't entirely sure if it came from Norse, but what's cool is that English needed a way to express different levels of blame, so we added -est to make guiltiest, showing how languages adapt to our moral needs.
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