Moblins carry large shields that are bigger than you! Fortunately, their shields are made of wood, making them easy fodder for your sword. The direction in which you slice them is reflected in the way they fall apart. Once their shields are out of the way, you can cut them directly. Watch out for their spear attacks, though - they're big and strong and can take out a decent portion of your life! If you dash directly at them, you can hop on top of their shields and over their heads to attack them from behind.
Find out more at Zeldapedia: Moblin.