The Cellular remains of a wound when large amounts of healing has occured in an infected area, such as a skin sweat or oil duct, a epidermal blood clot, or an ingrown toenail.
Laymans terms: That yellow, slimy, goopy stuff that splatters all over the mirror when you pop a zit, or pick your scabbs, or stub your toe.
When something is lame, dumb, annoying or stupid. Can be used as a exclamation. Various words can be added to emphasize this, like "wicked" or "double"
1. this test has 200 questions!? dude, puss.
2. Yeah, the party got canceled because the cops showed up. Wicked puss.