A job paid without taxes being paid to the government, so named because the money is being passed under the table which represents the government's tax structure. Usually, teens do small jobs for relatives, friends or neighbors and are paid in this manner, but shady adults will work usually illegal jobs in this manner. If you're young its usually better to work under the table as you usually aren't making much money in the first place, and taxes are no fun. Note that if you make a signifigant amount of income in this manner you probably will end up going to jail and it does happen.