A dog in the manger
Definition 1 of 1
Pro Tip 1/3Usage Context
Used for criticizing someone's selfishness, especially when they deny others something they can't use. 
He's keeping all these books just to spite me, such a dog in the manger.
Pro Tip 2/3Not Literal
It's a metaphor; no actual dogs or mangers involved, focuses on selfish human behavior. 
She won't let anyone else book the meeting room, a real dog in the manger.
Pro Tip 3/3Negative Tone
Conveys a negative judgment, implying pettiness or unnecessary possessiveness. 
He's a dog in the manger, hoarding supplies he never uses.