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4.
The combination of Sincere and Serious.
Dawg, I'm so sincerious. That shirt is hot.
by Brandon Brockman April 06, 2008
 
1.
A combination of sincere and serious. The realest of real.Handling yours and being unabatable or unstoppable. On top seeing nobody above you.
Kanye West's tracks and lyrics is so sincerious. Menh he aint playing bout making his paper he sincerious wit it. 10/20/05
by AnnonymousTipz October 20, 2005
 
2.
Having genuine sincerity (Comes from "serious" and "sincere") (Created by rapper Mos Def)
I told her I was sincerious in my apology.
by Curtis Meyer March 13, 2008
 
3.
A combination of sincere and serious. For when you are seriously sincere.
Are serious dude?

No. I am sincerious.
by Fukt Up October 05, 2009
 
5.
Being sincere and serious at the same time.
Jimmy: Yeah, RIGHHHTT.

Tom: No, I'm being sincerious.
by nesbolin July 10, 2009
 
6.
Sincerely serious.
I am sincerious when I tell you that I am horribly sorry I killed your dog, it was an accident!
by Jody Carlisle November 07, 2010