A situation in which there is no possible way to succeed. Usually not favorable, as winning is generally a good thing. Most often, one finds him or herself in a no-win situation after an innocent act that gets blown out of proportion.

Some examples would be:

Trying to have a nice discussion with extremists on their topic of interest.

Arguing semantics of rules with parents.

Getting caught in a risqué looking position accidentally and trying to convince someone that you were not doing something wrong.

Jokingly admitting something about yourself and having people believe it.