An adjective given when someone has mistakenly made themselves look dumb by saying something abnormally stupid in a conversation. Someone who disrupted, or killed, the conversation with a bad joke or comment.
"Dude! Guess what!"
"...You are really dephonicated, do you know that?"
To kill an otherwise good conversation with an abnormally stupid or unecessary comment that is not in any way relavent to the conversation.
(May be used as an adjective, ei; to be dephonicated by killing the conversation)
"OMG dave get out of here, you are so dephonicated!"
"OMG DAVE you just completely dephonicated our conversation!!!"