2 definitions by X. Phoratus

Any short shirt, such as a halter top, cropped tank or baby tee, that rides so high on a woman's chest as to expose not just the midriff, but also the bottom area of a woman's bust.
Damn, did you see her new underboob shirt?

Hells yeah! Ask her to reach for something off the top shelf!
by X. Phoratus February 21, 2005
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Hands down, one of the finest aspects of a woman's anatomy that can be enjoyed in any public venue.

Underboob is achieved by wearing a very short halter top or cropped tank, also known as an underboob shirt, which exposes the bottom areas of a woman's breasts.

Much like the combination of low-rise jeans and a thong, the underboob shirt can only successfully be worn by select few women.
In an ideal situation, a hottie will wear an underboob shirt to accessorize her low-rise jeans/thong combination. When this happens, all men in the vicinity will regard her as "hot" or "a sexy bitch", while their wives/girlfriend may refer to her as "trashy" or "a slutty bitch", but that's okay. Everyone knows she's a sexy bitch and they all want to do her.
by X. Phoratus February 21, 2005
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