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Acronym meaning "Fuck Me Sideways With A Crowbar".

Used to convey extreme displeasure with a turn of events, or when something doesn't go according to plan. Not usually used as a command.

Pronounced "Ef-Em-Swack".
"Dude, your girl just dumped you over a Facebook status."

"FMSWAC..."
by fmswac December 28, 2009
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