goodnessnoun (no plural)1being good or kind2something in food that is good for your health: Fresh vegetables have a lot of goodness in them.for goodness' sakewords that show anger: For goodness' sake, hurry up!goodness, goodness mewords that show surprise: Goodness! What a big cake!thank goodnesswords that show you are happy because a problem or danger has gone away: Thank goodness it's stopped raining.