Top definition
An accidental fart at the gym -- usually silent and occuring when it's hot and crowded -- creating a thick, pungent, unpleasant pocket of air during a moment of physical exertion. Commonly occuring near the treadmills.
The gymission of the girl on the treadmill near the drinking fountain made filling up my water bottle an unsavory experience.
by D-Diamond June 22, 2011
Get the mug
Get a gymission mug for your daughter Yasemin.