An overcooked dish is one that's been cooked for too long, and now it tastes burnt or tough. This can happen when you forget to check on your food while it's cooking.
When people talk about something being overcooked, they usually mean a meal that they were looking forward to eating. Maybe someone made a big dinner, but then left the veggies on the stove for too long. Now they're all mushy and taste bad. You might hear a friend say, "I made a nice steak, but it was really overcooked." This means the steak is dry and doesn't have any flavor. It's like when you try to eat something that's been sitting out for too long – it just doesn't taste good anymore.
To cook for too long or at too high a temperature.
Made unpalatable or inedible by cooking for too long.
