cleavage visible from the part of the shirt that covers the bottom of the female breasts
If that is not a deliberate underboob, I don't know what is.
by The Return of Light Joker March 21, 2009
Get the underboob mug.
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
Get the underboob mug.
Underboob: The only time in life when gravity is your friend.
"She's got underboob, so there's a small chance her boobs will slip out of her top, thanks to our good friend GRAVITY"
by flargenschmop March 28, 2010
Get the underboob mug.
Generally, when a women wears a short cut top/pulls up their top to cover all but a portion of the bottom of the breast. Nipple can be shown, but often it is also covered.

Other ways to achieve underboob are: Handbra (covering the breast in the same way a short cut top would), or viewing from a low angle so that the point of view is looking up at the woman's breasts.
That woman's top gives her great underboob.
by JeffryGoldbloom February 3, 2016
Get the Underboob mug.
The act of hitting the underside of one's breast with ones head in one swift motion
"I keep getting underboobed!"
"When he underboobs me it hurts!"
"For some reason she enjoys underboobing people"
by magicalunicorns0509 September 29, 2014
Get the underboobing mug.
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
Get the underboob shirt mug.