McDojos are schools that are run and owned for the purpose of making money. Typically you are able to get a black belt in less than 2-3 years, and you are usually guranteed success on the black belt test. These schools charge outrageous amounts of money, have extensive contracts, and are sometimes cult like.
"I had to pay $3000 a year by contract to go to this mcdojo, I could not pay by the month"
"That McDojo is stupid, you won't learn anything and your bank will hit the fan."