Forfiet is what occurs when a team can not field enough players for a match. They will forfeit the match and all points will go to the opposing team.
A default is what we use when we are recording the scores in TopDog. When you are entering scores for a forfeited match, you record a win next to the name of the club that did not forfeit. Then you place the name default in each position where you would normally place a players name.