A crippled majority is a very bad thing to have in the endgame. It is when you have more pawns on one side of the board but you can't create passed pawns with it because it is somehow blocked. Here is an example:
These majorities are worthless and usually allow your opponent to have a healthy majority on the other side. The good thing is you can straighten things out with trading off weak pawns. There is also another trick besides doubling pawns to give your opponent a crippled majority. On the queenside, white used this and could stop both black pawns from promoting. Hope you had fun learning and feel free to comment and ask questions.