Superlative form of guilty: most guilty.(adjective)
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Use "guiltiest" in a sentence
"I used to read some mystery series as guilty pleasures (the guiltiest were the Stephanie Plum books by Janet Evanovich), but I've mostly given up on those for time constraints -- and, in Evanovich's case, because I finally realized the heroine would never learn anything and I needed to stop beating my head against that particular wall."
"Perhaps Waters '"guiltiest" admission might have been the desire to, if not become a "mainstream" filmmaker (on his own terms, of course), then at least have access to more of a mainstream audience than would have even glanced at an ad for"
"Still, the classic Range Rover is the guiltiest pleasure since the Sack of Rome."