What is Selwyn?
1.
a really fat kid who gets on everyone's nerves and cries when your class is late to lunch, or he doesn't get a grilled cheese sandwich!
beth was acting like a complete selwyn when we wouldn't talk to her.
See
2.
A Selwyn is pretty much when someone tells you they're going to do something, then either doesn't do it, or just completely fails in that sense, usually ruining that section of the day or just making it annoying to be around.
It is a worse version of admitting defeat or a
Guy #1 "Remember that time Selwyn did a Selwyn on us?"
Guy #2 "Don't remind me."
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