a gargantuan obese slab of fat/lard, located specifically on a girl, sometimes boy. often described as a paunchy whale. a blunderbuss is often found drunk in the hottub, at the mall trying to pick up boys, at the back of shows trying to be "scene", (you can always find it eating in any situation including these i have described), a blunderbuss will also buy shit from bands it has never heard of and then later say they hate the band. a blunderbuss is very very very very ugly/fat/fake/emo. he/she will cut themselves and take pix of it and put it on myspace to look "cool". she, i mean it, will take any guy or girl he/she can get. EVEN IF THE GUY IS FROM GEORGIA AND THE BLUNDERBUSS LIVES IN MICHIGAN!!! usually a blunderbuss will think its the shit and think everyone else is below them.
so pretty much to sum it all up, a blunderbuss is a fat fake emo stalker =D...feel free to add if you feel the need to =

A mass shooting.

A butthole of a mid 40’s male which has the ability to spackle the inside of a toilet with equal parts elegance and pizazz.

A gun with a flared muzzle or disorganized activity.