Not traditional, or departing from tradition(adjective)
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Use "untraditional" in a sentence
"Review: Williams, who specializes in untraditional science fiction, has created an ambitious novella (140 pages!) that's two parts fantasy and three parts mind-blowing sf."
"Have you seen this book (with a very odd name: How the Other Half Worships) that is full of photos of American churches in untraditional settings?"
"Former President George W. Bush, a k a The Decider, has released a video about his forthcoming memoir, "Decision Points" in which he describes his "untraditional" approach to the writing."