What exactly is E-Peen and why do people get/use/whatever it?

I heard this term - E-Peen. What is it exactly? I have heard it is something got to do with showing off, and a bit of self superiority, yet the name suggests a different meaning.

Like people said
"Some people get a 5.0 GHz unstable overclock just for Epeen"
"Some people just get rare epeen gear"
"6950X for gaming is eppen (sic)"

I would like to know exactly what it means when a person says that in comment, be it Youtube or Forum comments. Thank you in advance!