A person who is a combination of a Loser, idiot, clutz, bigot, naive, arrogant, oblivious and generally lacking insight to the world, very opinionated but is never perceived as a smart or charismatic.
This person will often find him/her self in awkward situations, often without realising it. Someone who will say inappropriate things at the wrong time and thinks its all cool.
A: "Did you hear nathan talking about how great his new headphones were to the grooms mother"?
B: "Yeah what a goober"
A: "That dude is walking around the beach chatting up every chick with his ridiculous hat"
B:"Yeah what a goober"
A:"I spent my day driving around in my new car to see who would look twice"
B:"Dude its a 1993 Mazda 121 you fucking goober"