bar, etc) whom has failed to hook up, or pull. either because of their apparent lack of game or just because they are unatractive unless you've consumed massive ammounts of alcohol. Usually the later. They are usually preyed on by those who choose to get some action easily.
Bottom Feeders are also found in large numbers at dive bars usually in groups.
Beware there is always a Cock Blocker in the bunch!!
There is also a good chance there is a good looking girl in the group, bottom feeders keep her around to attract the single guys hoping that they will talk to them instead of their hot friend. The opposite of this is that the hot girl has low self esteem and hangs out with the bottom feeders to make herself feel prettier.
she is also easy pickings...
"its gettin late, time to fish for bottom feeders"
"bottom feeders at 8 o'clock"
"im trashed bring on the bottom feeders"