An escalated form of the slang term "sick" or "tight". Fair is used as describing something as beyond good , not to be mistaken with the "Fair" meaning average or normal.
1) A term used when the listener of a conversation has no interest what so ever in what you have to say but thinks you should care about what they say.
2)A term used by the socially inept to destroy a convasation
1) "That movie was great"
"It was ok they could have improved it by (whatever)"
"Fair"
2)"So I said they should offer me some sort of refund, how can they rip people off like that?"
"Fair"