One who casts off the restraints of a conventional life to pursue their passion(usually something dangerous and off the wall like base jumping, rock climbing, surfing etc.) Often you will find them living in vans, buses, caves or tents. Usually broke but always smiling.
Girl: Mommy, I never want to grow up. Mom: Well Dear, learn to climb, buy a van and become a dirtbagger.
Being at a certain point of desperation where you'll reach over to another table and help yourself to the unfinished drink of someone who's left the lounge. Common practice of stressed-out folks about to head into a sales call, going through divorce, or just want to put the "seed" in "seedy", and need that extra drink. Usually practiced after one has had a couple of drinks (to, ya know, establish that you "belong" in the establishment), and desperately reaches for some abandoned beverage in a knee-jerk, fuck-all gesture.
"Dude--drinking that beer that guy left is pretty dirtbag."
"You wanna go get drinks later--maybe a bit of dirtbagging?"
The study of being a dirt bag. or specializing in being a dirt bag by accumilation of your actions.
dirt- bag-ge-tree
being a dirt bag or shit bag by trait.
being an asshole all the time
The court ruled she was guilty of DIRTBAGGETRY by sleeping around with all her husbands co-workers , there for the domestic violince charges from her getting beat by her husband were dismissed.