Deduchional 

Used to describe a man who believes he is truly the most amazing creature on the planet. Regardless of his advanced age, hair (or lack of if), weight, skin type, high-pitched, whiny voice and Mr. Roper clothing, he feels he’s entitled to the perfect companion. In all his douche glory, he is not afraid to profess this sense of entitlement at bars, during dinner parties, at the office or on his personal Web site. Can also be used to describe a woman who shares the same delusions of grandeur.

Example 1:
“She’s hot. Let’s go—you’re gonna be my wingmen.”
“Dude, stop with the deduchional b.s. She wouldn’t talk to you if Justin Timberlake and Zac Efron were your wingmen.”

Example 2:
Sarah Palin said she is quitting her job to do a better job for Alaska. That is so deduchional.

Deduchional by Trish77 and 2e July 6, 2009

Black Dynamite Deduction 

Where one deduces a solution to a problem or mystery by taking one clue and bringing it to another in a long chain of paranoid connections until it leads to the conclusion. Named after the famous ''Anaconda Malt Liquor Conclusion Scene'' in Black Dynamite, where the titular character somehow realizes that Anaconda Malt liquor was the government's secret weapon after Bullhorn said "melt in your mouth", making several arbitrary connections until it led to the answer.

*Gasp* "Human being"? That word kind of sounds like "bean." Beans are legumes, "legumes" has the word "leg" in it. Ian's mom has really nice legs, and Ian's mom is so old she's practically dead, which can only mean one thing! Oh my Bieber! YOU'RE BECOMING A ZOMBIE!
--Anthony Padilla from Smosh using Black Dynamite Deduction to deduce that Ian Hecox is becoming a zombie

Black Dynamite Deduction by The Logical Fallacy July 16, 2016

Weapons of mass deduction 

Taxes or else other methods of removing the working people's hard earned cash. Typically utilized by the man, these weapons are a crime against humanity and a sin against nature.

Tom: Who in the name of Ayn Rand do the IRS think they are, taking my pay from me? I don't owe them two farts!

Dave: Too bad they have those bloody weapons of mass deduction.

Weapons of mass deduction by Colonel Duke Lacrosse December 1, 2011

detuction

a guy who came up with this word, he plays a roblox game called Rogue Lineage. He is the coolest, slickest and most peaceful guy you'll ever meet in Rogue Lineage. He is a pacifist and rarely and barely attacks others.

Person 1: OI, DET (ABBREVIATED VERSION OF DETUCTION) SHOULD WE GANK THIS ULTRA?

Detuction: Nah, hes too strong. Lets leave him alone.

detuction by Ace Lawliet January 17, 2021

deduction 

A physical or personal/social characteristic which necessitates a loss of points on the physical/social attractiveness scale (as figure skaters receive deductions for errors in their routines)

Super butt and danced it off, but talked about herself all night and hasn't brushed her teeth in a week--major deductions.

deduction by Dr. Foo February 20, 2009

standard deduction

The traditional Lenten sacrifice of abstinence from non-seafood meat (beef, pork, chicken, lamb, etc.), as opposed to any additional sacrifice like chocolate, beer, video games, or sex.

GF: Are you gonna give up playing Guitar Hero for Lent?
BF: Hells no, I gotta finish it in hard. I'll just take the standard deduction.
GF: Step aside, then. I just need to beat "Free Bird" in expert to finish the game. Nooch!

standard deduction by resident alian February 19, 2008

Fisher's deduction 

The more issues a person crudely shoehorns down into a liberal/conservative dichotomy, the more certain you can be that the person is an American

Exact origins are unknown, but Fisher's Deduction is a maxim or meme found in USENET and other online discussions, similarly to Godwin's Law.

Fisher's deduction by office glen November 14, 2005