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 neverwant togrow up. Mom: Well Dear, learn to climb, buy a van and become a dirtbagger.
A word you randomly say out of frustration while playing call of duty black ops, or any other online game such as halo. This word usually means a faggot camper who doesnt know how to play the game right and all he does is crouch in the corner.
1: Hey have you heardDancing in the street?
2: Yes, I ship Dick Bagger ever since
1: Me too, did you know it was confirmed by bowie's ex-wife, she found them post-coitus and just offered them coffee.
2: SO COOL!