What is the meaning of 'dog in a manger'?

manger meaning Manger Surname Meaning: English: Dutch and German: occupational name for a retail trader Middle English: manger, monger Middle Dutch: manger, menger

Manger Surname Meaning: English: Dutch and German: occupational name for a retail trader Middle English: manger, monger Middle Dutch: manger, menger  manger png ​a person who stops other people from enjoying something that the person cannot use or does not want themselves See manger in the Oxford Advanced American