The act of making someone believe a joke, statement, etc. is true, while it is in fact completely fake.

Usually the person being januaried will try very hard to figure out what the person meant, making them look like a complete and utter idiot, as they meant nothing. Added people who are in on the january will add to the hilarity.
The most common use of the term is through the "January Joke":

Person 1: Yo, what month comes after June?
Person 2: July?
1: Are Julying to me?
2: Ha ha ha very funny.
1: Ok listen to this one: What month comes after December?
2: January.
1: Are you Januarying to me? *Everone "in" on the joke starts laughing*
2: (Embarrassed) What? I don't get it. What do you mean?

When someone is found out:

Person 1: Dude I brought home like 20 chicks last night man!
Person 2: Yeah right, you're januarying me...
Person 1: Damn you got me.
by dickmasterflex September 21, 2010
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Nantional Hangover Month. Because of the recent holadays and masive partying the general population spends the month hungover
"Crap I have to go back to work. Wait, Its January which means my bose will be hung over too
by Vlack August 20, 2008
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Everyones favorite month!!

playing in the snow
snuggling by the fire,
and having excuse for ur penis looking so small.
January: Cold weather shrinks ur junk.

by jimmeny hensworth August 26, 2008
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1) A one of a kind cool ass girl.

2) The shit on a stick. (In a metaphorical and good way.)
Girl: Who is that chick?
Other Girl: She's Januarie. She's the shit.
Girl: DAaaamn she hot.
by itchyiris March 22, 2010
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People born in January are kind and a little selfish. They have great talents but are shy about them because they are worried that someone will hurt them. They switch around friends because they feel a bit unwanted and uncomfortable but once you get to know her they are SO FUN. They aren’t suck ups to teachers but they try to get good grades and stay on the positive side.They try to be popular and nice to everyone. They are super positive and always smiling.
Hey who’s that?
That’s Emma
Wow she looks so positive and happy!
Yeah she was born in January
by Idk_what_im_doing_here.17 November 6, 2019
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It’s an important month considering it’s just after Christmas most people find it depressing but it is actually National egg a house day, where through the whole month you can egg someone’s house or be egged.
It’s meant to cheer you up since it’s a depressing month.
James:”Why has my house got eggs all over it?”
Sam:”Because it’s January, National Egg A House Day!”
James:”Oh that makes sense.”
by Har Har Cowface December 2, 2019
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The worst fucking month of the year when it comes to memes and YouTube monetization.

You are much less likely to be monetised in January, and very often nothing of note happens. If it does, like Logan Paul's suicide forest incident of 2018, then you are likely to be demonetised due to the controversy.

Memes are also at an all-time low for the year in January, with an incredibly short shelf life and low in spiciness. This is proven by the Ugandan Knuckles, Somebody toucha my spaghet and Big Chungus memes all occurring within the January of their respective years.

January is known to be "YouTube Hell" for many, or "Demonetisation Hell", or the "Month of the Sea of Yellow Dollar Signs".
Random commentary YouTuber: "It's a January meme. Not only will I not be able to make a funny video out of it, but I won't get monetised!"
by Mickey_G_ April 24, 2019
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