Runderwears 

tiny pants? that serious runners wear; resemble underwear but are athleticky

Wow look at how fast she runs in those runderwears! The lack of fabric must make her so aerodynamic

Runderwears by cgod March 28, 2019

Underwears in the air

When someone is showing alot of attitude, it is appropriate to use the phrase , "THERE ARE UNDERWEARS FLYING EVERYWHERE IN THE AIR!!!"

GUY 1: Oh my GOD!!! YOU LOOK SO LIKE FUGLY EIEWWWW

GUY 2: OH MAN THERE ARE UNDERWEARS IN THE AIR!!!! I THINK A HOT PINK UNDERWEAR JUST GOT STUCK ON MY FACE

Underwears in the air by T'Resa November 3, 2018

runderwear 

The skin-tight underwear that comes pre-sewn on a pair of super duper short running shorts.

timing girls: "Holy shit, you're not wearing any underwear!"
super fly runner guy: "I, as a matter of fact, am not. I am wearing runderwear. Look!"

runderwear by teeeheeee October 31, 2008

runderwear 

The undergarment worn on the waist to thigh and pelvic region when running, either for exercise, sports, pursuit or evasion. This undergarment absorbs perspiration and holds the genitals intact. It should not be worn continually after running, and should be washed soon afterwards.

"When I finished jogging at the track today, my runderwear were soaking wet and quite pungent!"

runderwear by Joefeather May 15, 2013