slang A euphemism for "fucked" (using the spelled-out version of its first letter, "F"); in a problematic or daunting situation; certain to fail or experience the worst possible outcome; doomed. Dude, we are so effed—mom is on her way home from the airport, and the house is still a wreck from our party! I knew I was effed when I found out my enemy was on the recruiting committee.