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9.
To blow a load and run. AKA drive-by.
I can't believe he pulled a blow-by. I'm never speaking to him again. What a jerk.
by Jolie St. Laurent April 09, 2006
 
1.
The foul smell of a fart that has gained momentum by passing by a turd before exiting the rectum. Usually accompanied by a prairie dog. Scent is thick, heavy, and smells like shit, rather than gas.
Ashleigh, is that blow-by I smell?
by Dr. Duty September 04, 2012
 
2.
A condition exhibited by a worn-out internal combustion engine when the piston rings no longer efficiently seal the combustion chamber, allowing compressed air and fuel to escape the cylinder and thus power is lost and emissions are increased. The engine also usually burns oil.
I was going to buy that 350 from Carl, but it had too much blow-by and needed to be rebuilt
by FlYhEaD January 20, 2005
 
3.
Gas that escapes between the wall of the anus and the poop that needs to come out.
Hey Ralph, you smell that! I have to shit so bad I've got blow-by.
by Elvis October 18, 2003
 
4.
A burp collected in the mouth and quietly blown into an unsuspecting victim's nose.
After a burning sensation in her nose, The Baub's wife realized that Jr. perpatrated a perfectly-timed blow by. It smelled like a dead and bloated kangaroo stuffed with used baby diapers.
by L'Regis April 24, 2007
 
5.
1)Blow-by occurs when the explosion in your engine's combustion chamber causes fuel, air and moisture to be forced past the rings into the crankcase. Your engine's rings must maintain an excellent fit in order to contain the pressure.

2) Blow-by also occurs when somebody who REALLY needs to take a dump lets loose a fart so putrid and heinous, that it smells as if he just crapped his pants.
Daaaaamn Shecky! *cough* Judging from the stain on your trou, that wasn't mere blow-by.
by sophistiKate September 08, 2011
 
6.
The small amount of wet shit that ends up in male underwear after urinating, usually caused by farting or a relaxed anal sphincter.
Mom: "Goddamit it Sol, look at this blow by in your underwear!"
Son: "Oh fuck you, just do the laundry and shut up."
Mom: "I swear Sol, sometimes I don't think you're my son, or Jewish, or enrolled at Penn."
Son: "Suck my soulja boy, Mama."
by SollyTude July 15, 2008
 
7.
Similar to drive-bys. However in this case the act is to satisfy an acquaintance by driving by in a 20-inch rimmed car, dropping a 'ho' out and allowing him to suck the acquaintance's cock.
That snoop dogg fellow is capital. I must send my bitches on a blow by
by Spencer February 03, 2003