A French fry that falls out of its container and onto the bottom of a paper take-out bag. Sometimes found in twos, other times found in large groups with other bum fries creating a greasy bottom. Bum fries are in no-man’s land, hence are up for grabs by any party that shares the same take-out bag.

You use this word when you are referring to someone who is being lame or has a tendency to be lame.