What is an unauthorised overdraft? How much u. o. can you take out of your account?

unauthorized overdraft is just a fancy way of telling you that you screwed up. They charge you overdraft fees and you only get one chance to overdraft, like if you spend all of your money at walmart and then you go to mcdonalds and the bank doesnt realize yet that you already spent all of your money, then you overdrafted, and its too late bc you got your food but once everything clears, you wont be able to use the card anymore until you deposit money.