Lacking coverage over the area of the crotch(adjective)
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Use "crotchless" in a sentence
"Gobs of saliva drip onto her strapless black corset and matching crotchless g-string."
"I mean, how crazy is it to look into your family history and find a great-grandfather who got his start in this country by selling crotchless underwear to brothels?"
"As for accessories, you'll find crotchless panties, remote controlled vibrating panties, and even a "Lover's Thong" with "sensual pearl-finish stroker beads.""