Exotic currency pairs are currency pair that are not traded as much, they are from the emerging market like USD/SGD (Singapore dollar) . 'Exotic' in foreign exchange term used for currency that is not in use that much meaning it is not liquid and has wide spread!
Some exotic pairs are profitable. They are not too volatile, but have a predictable movement. This is good only for long term trades. Others are less volatile and less predictable but can move drastically and put you in trouble.