A view of the female breast seen from a side; generally under loosely-fitting clothes. Very titillating (pun intended) and sexual without showing any overt nudity.
There is so much sideboob at Los Angeles awards shows!

My brother's g/f's sideboob totally distracted me from my own g/f.
by Nutty J September 17, 2005
A view of the female breast seen from the arm side; generally under loosely-fitting clothes. imghttp://www.tsbmag.com/wp-content/uploads/2007/09/natalie-portman-side-boob.jpg/img
There was plenty of sideboob on show at the awards ceremony.
by wirby January 23, 2009
The side of a woman/mans boob
''How about this sideboob? You like that huh? Well thats my sideboob'' -Peter Griffin, Family Guy
by Bambieyes16 January 21, 2009
The two outside stunt groups of a cheerleaders pyramid.
The Lyndhurst coach said,” the middle of the pyramid looks good, but the sideboob needs work.”
by A Lyndhurst Cheerleader October 12, 2018
Sideboob is the registered trademark of a fashion line by the company Some Brand in Germany (www.sideboob.de). The name Sideboob originates from their renowned shirts with deep and wide side cutouts, which allow a view of the female and male breast seen from the side.
I love these SIDEBOOB Shirts, because they allow a nice view of her breast from the side. Show some sideboob!
by Zischerio August 30, 2013
A view of the breast from the side that is really only good-looking on hot women with large tits, and if pretty much useless on small-titted cunts.
Joanne has really small tits so her loose dress made her sideboob look like filth.
by Andromeda1232 January 18, 2009
An abnormality where a boob grows on the side of the torso, usually under the shoulder.
If she lifts up her arm you can see her sideboob.
by Wrong Un January 16, 2009