A verb -

To seriousize

Present tense:

I am seriousizing
You are seriousizing
He/She/It is seriousizing
We are seriousizing
You are seriousizing
They are seriousizing

Past Tense:

I serious'd
You serious'd
He/She/It serious'd
We serious'd
You serious'd
They serious'd

It is what you do when you need to look serious. You serious.
"Jim was laughing, but then he serious'd because his mum came in."

"Could you guys seriousize a bit?"

"Yo dawg, us street-ghettoistics be seriousizing!"

"To seriousize. Or not to seriousize. That is the question."
by Yonasu June 28, 2008
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Used to back up a statement that is strongly true.
Person A: Dude, the performance of Berlioz's "Symphonie Fantastique" was the best thing ever!!

Person B: For seriously!
by Sho Fo-Sho March 09, 2009
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When she spoke to the crowd, her tone was one of seriousness.

His face showed intensity and seriousness as he strove to define "seriousness."
by Bill Foecke October 09, 2003
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asking a question, slang word for emotion thats serious
jason: "she broke up with me and she wasn't even kidding, she was seriousing"
alex: "dude are you seriousing me? you guys went out for 3 years!"
by aakasd420 October 20, 2010
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This term is usually used after saying a non-intended humorous quote or phrase.

This term can also be used to put a serious twist on your joke, and frequently intensifies the situation.

It is also used to make a joke more humorous, this is called backing-up(usually used after your not-so-funny-joke)
#1:
Person 1: Yeh i got a vest the other day!
Group: HaHahahAhAh
Person 1: but seriously

#2:
Person 1: I've got a vest....jokes....but seriously
Group: HaHahahAhAh

#3:
Person 1: Vest are only for 'homos'
Group: *cough*
Person 1: but seriously!
Group: HaHahahAhAh
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