a fart, or pass wind, often reffered to as a person who is as valueable as passing wind
e.g. billy bob is such a bumblow
by vinstar November 04, 2005
To blow one's nose by pressing down on either nostril and blowing the snot out of the other. Used by people who don't have tissues or are homeless (bums).
Whenever I don't have a tissue, I just bum blow to clean my sinuses.
by Prizio February 27, 2004