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mainliner 

One who injects drugs into their bloodstream with a needle.
Ohmygod, he's not only a mainliner, he reuses his works! Do not exchange any bodily fluids with him no matter what.
mainliner by mjrn April 11, 2006

mainlining

the intravenous injection of a drug. which means using a needle to get a drug into your vein, to absorb it through your bloodstream. a lot of drugs can be taken this way, the most commonly associated drug being heroin.
Layne accidentally overdosed by mainlining heroin.
mainlining by two blue lights December 9, 2008

coefficient of manliness 

It is a coefficient calculated by dividing your " penis length" by your height and then multiply the result by 100. (MaN=(penis length/height)*100).We measure it in cm and the final result will show us the percentage , how much of your body height is your glory.
What's your manliness coefficient?
I've got higher coefficient of manliness than you
What is your boyfriend's coefficient?

mainlander 

Referring to the Chinese who are not Hongkonger, people form Macau or Taiwan. So few of us are not Communists. These people are awful according to anyone who is not from the Chinese Mainland. But if you actually get to know some younger people with good education (or some who are not studying in the terrible brainwashing school system/studying abroad) they are normal/nice people just like most human beings.
A mainlander can be a devil or a good person, it depends on who you meet in life.

mainline 

To inject a drug, usually heroin, into a vein. Also used to refer to the drug itself.
"That chick was mainlining heroin daily till she OD'd."

From Queensryche - Operation Mindcrime:

"Had a habit doing mainline
Watch the dragon burn
No regrets, you've got no goals
Nothing more to learn"
mainline by eidolon July 17, 2004
A dude who surpasses many other dudes in his dudeliness.
Adam.
Someone might say "Dude, that dude Adam is way manlier than I am."
manlier by the nelius July 7, 2007
More from Urban Dictionary

square grouper

Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."
square grouper by slipsheet November 6, 2004
Word of the Day on October 7, 2026
A girl who does ballet and only talks about ballet. Her schedule is filled with dance classes which does not allow her to do any other activity.
"Hey, do you know that girl Sally?"

"Yeah, she's kind of annoying. All she ever talks about it ballet."

"Wow, what a Bunhead."

"Hey Sally, you want to hang out this weekend?"
"I can't, I have dance."
"You're such a Bunhead."

"Yeah... I know."
Bunhead by Jen00 October 24, 2014
Word of the Day on October 6, 2026

trucker's tan 

A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
I had a trucker's tan after driving for 10 straight hours on a sunny day.
Word of the Day on October 5, 2026
The phenomenon where adults salivate at children's toys
Every time I walk into the toy aisle, I catch myself kidulting over the latest action figures and LEGO sets!
kidulting by Emotional Cruiser October 12, 2025
Word of the Day on October 4, 2026
British slang for a scientist or technical expert, esp . when the speaker is not certain of the expert’s specific field of study. Not necessarily derogatory, but typically used by persons without a technical background. In the US, the equivalent would be “egghead”, “squint”, or “geek.”

Origin of the word is unknown. Started sometime in World War 2. Given the typical evolution of British slang, could easily have started because what these experts did was confusing or “baffling” to the common person.
According to the boffins downstairs, the murderer used a serrated blade.
Boffin by Agnon February 11, 2023
Word of the Day on October 3, 2026
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