Some abilities in Mdot are armored. Usually, slow charging and high damage moves have armor on them. Earth moves in general tend to have armor on them as well.
Having armor means that your monster’s current ability cannot be interrupted by enemy abilities that don’t knock your monster down. Your monster is also immune to knock back force.
This allows you to counter fast and weak moves with slower moves that have armor.
If your monster gets hit while armored by a move that doesn’t knock your monster down, then a yellow shield effect will appear.
After absorbing one hit however, the armor is gone and the next hit is able to interrupt the move. For this reason, mutli-hit moves are good counters vs armored moves.
Some moves have Persistent Armor, meaning that the armor is always active for the duration of the move.