A word with no meaning which you interject as a practical joke into sentences to prank your friends and colleagues. Laugh into your sleeve, taking note of any and all who believe it is a real word.
Option one:

“The project is coming along well, the designs are being a bit sefarious, but apart from that, everything is great!”

*Person stares blankly.*

Option two:

How was your weekend?

“It was sefarious!! The mountains were gorgeous, the waves were beautiful... truly sefarious!”
by ArchangelZadkiel3 November 28, 2020
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It's like nefarious, but not, because it means awesome.
Mohamed Dahak: "I'm going to a sefarious party tomorrow night"

Aryan Arwin: "oh..good..?"

Mohamed Dahak: Not good....SEFARIOUS!!!!!!
by C-deedle March 05, 2008
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