The characteristic or quality of being gruesome.(noun)
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Use "gruesomeness" in a sentence
"The gruesomeness is in your mind, we both hunt and kill living things to eat them, why should one bit of gristle be more gruesome than another."
"As others have pointed out, compared to the crimes for which he was being executed, one has to wonder if the gruesomeness was a bug or a feature."
"Equally plainly, the scripts consistently fail to find the balance between gallows humour and the sheer gruesomeness of forensics work that you'd find in even a half-decent episode of CSI."