Missional church is a difficult thing to define. You can sometimes capture it by saying what it isn’t. At the risk of being simplistic, you could say that Missional isn’t Attractional. Attractional church is the mindset that what has created the current crisis in your church is poor promotion of your church. If you advertised, did things better, offered more programs, the people would come. Attractional church says, “Come and see us!” Missional church says, “Let’s go and be Christ.”
Geoff Surratt has a great video post on the dangers of Attractional Church.