The characteristic or quality of being grotesque(noun)
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Use "grotesqueness" in a sentence
"But in spite of its merits, its dialect wearies the modern reader, and gives it an air of grotesqueness which is very alien to the spirit of the Latin."
"Even in its miraculous element it stands to some extent in contrast with all mythologies, where the marvelous has ever a predominant character of grotesqueness which is absent from New"
"This description of the Foul Fiend has an element of grotesqueness which is rather Christian than Moslem."