This idiom describes someone who selfishly prevents others from using or enjoying something they themselves cannot use, like a dog lying in a manger, blocking livestock from eating hay it cannot consume. It conveys pettiness or spite, often used in social, workplace, or personal contexts to critique selfish behavior.

The phrase carries a tone of scorn, irony, or moral judgment, reflecting cultural values of fairness and the human tendency to hoard or obstruct. Its animal imagery evokes a vivid, petty act, resonating in scenarios like resource disputes or jealousy. The idiom condemns selfishness, making it a sharp metaphor for obstructive behavior.

The phrase originated in ancient Greece, from Aesop’s fable *The Dog in the Manger* (6th century BC), where a dog blocks oxen from hay. Its English use emerged in the 16th century, with John Lydgate’s *Troy Book* (1420) referencing the fable. The idiom gained traction in 17th-century Britain, notably in Francis Bacon’s essays (1625), and spread through moral literature, with Charles Dickens’ *Bleak House* (1853) using it for selfish characters. Its adoption across English-speaking cultures stems from the fable’s universal lesson and vivid imagery, enduring in critiques of selfishness.