An abbreviation of the word "sustainable" used to quickly tag any positive, environmentally-sustainable action, thought or deed (or to dis any stupid, NON-sustainable action thought or deed).
I see that you're now using a two-sided printer; very susty!
Bottled water is NOT susty.
I'm telling you, it's susty to shower with your buddy!
Hey, your driving one fucking block to pick up smokes just ain't susty.