Superlative form of harsh: most harsh. Most severe.(adjective)
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Use "harshest" in a sentence
"His crackdown on whistleblowers has been called the harshest and strictest in US history."
"The rebuke, the harshest from the Chinese government since the violence last spring, contributed to the breakdown of talks between Chinese officials and envoys of the Dalai Lama that had been taking place since 2002."
"The freak weather, described as the harshest to hit some areas in 40 years, has affected the South Island and swept up the North Island as far as Dargaville, some 80 miles north of Auckland."