Comparative form of shrill: more shrill(adjective)
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Use "shriller" in a sentence
"The protesters' calls for greater income redistribution and their denunciations of capitalism have become shriller, and the protests are becoming more violent and destructive."
"Maybe he needs to get out there and be more on the hustings with a shriller voice than the one he's demonstrated."
"The one-minute floor speeches and longer floor debates are becoming shriller and more personal, and the basest of all political instincts now have a viral host to go global."