1. someone whose mind is closed off to accepting new data, because of a false conclusion they have accepted as fact.
2. A student with learning disabilities that they don't recognize or accept.
Faculty member 1: That new student had a full scholarship and decided education was beneath his calling and dropped out.
Faculty member 2: It is for the best anyways, because he is academically concluded.
When someone's high, but you don't wanteveryone to know. It can be used around parents and just generally adults as a way to covertly mention how stoned your friend is. This usually only works if the concussed person participates in some kind of sports.
Friend #1: Dude what's up with Jerry?
Friend #2: He took a reallybig hit and now he's concussed