"Somebody Else's Problem", an effectively-magical field that obscures things you think aren't relevant to you, such that even though you see them (or hear them or read them) you don't actually *notice*, and quickly forget.

More generally, the phenomenon that causes people to ignore issues that they know about but think of as either not something they can do anything about, or not personally relevant to them right now. This can result in something that's very important to a group of people being ignored by every individual member of that group.

Popularized by Douglas Adams in the "Hitchhikers Guide to the Galaxy" series, in which Ford Prefect describes it as:

"An SEP is something we can't see, or don't see, or our brain doesn't let us see, because we think that it's somebody else's problem.... The brain just edits it out, it's like a blind spot. If you look at it directly you won't see it unless you know precisely what it is. Your only hope is to catch it by surprise out of the corner of your eye."

In that series, a strange object can be effectively hidden from view while out in plain sight, by an "SEP field", which "relies on people's natural predisposition not to see anything they don't want to, weren't expecting, or can't explain."
It's just been sitting there all day, hundreds of people have walked by, and nobody said anything or even turned to look! It's like it's got an SEP field around it.
by my name is Cos July 11, 2008
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GENERAL SEP!
Look it's general SEP! I hope he doesnt eat my balls.
by Sep hater January 3, 2022
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when your out eating with friends or doing any activity costing money, paying separately or individually; not paying together.
waiter: "can i ring you guys up?"

group: "yes, but we'd like to pay seps if possible"
by jay moody March 24, 2011
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A girl who loves the cock. Mainly someone with the name Bob, perferably Big Bob.
Man, Sep Sep is such a good cock sucker!
by Big Bizzle 78 December 22, 2007
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Literally, "Some Else's Problem," as coined by Douglas Adams in Life, the Universe and Everything, the third book of the The Hitchhiker's Guide to the Galaxy series.
Your website is offline? Sorry, that's an SEP.
by dwardio July 29, 2008
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The nickname for a person named "Septimus"
Jenna: Sep, wanna go to the tower?
Septimus: i wish i could but i got an exam i have to study for.
by 123123sora November 27, 2010
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Sepping is the action of sliding in the private messages of a person you are interested in right after adding them on the social media of choice
" hey man i see you just added Julia on facebook"
" Ya man im about to sep in her dms"
by Ge_def September 24, 2016
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