1 [defintion]
When someone holds a cryptocurrency through a pump and dump, they are left holding a bag (useless coin) that they bought for much higher than it's current value, and therefore they are stuck with a bag no one wants - a bagholder.
2 [definition]
Someone holding onto an asset going towards zero
3 [meme]
A bagholder is every individual holding onto crypto assets

* All terms and definitions may change as the Cryptionary improves