A fork of Rural Dictionary
Short for "nightmare".
Bad luck.
Unfortunate circumstances.
Usually "having a mare".
Having a bad day - "Dude, I'm having a MARE!"
Watching sports on TV - "Oh, man, Yao Ming's having a MARE!"
Eavesdropping.
I believe I first heard this in a Goon Show (british radio comedy from the '50's)
Oi! Quit earwigging on my conversation!