Other names for "green-eyed monster" : "envy" and/or "jealousy" The green eyed monster is just a way of saying jealousy of most of the time, a rival.
jealousy
Jealousy is like a green eyed monster.
Jealousy.
The green eyed monster.
Oh beware, my lord, of jealousy It is the green-eyed monster which doth mock The meat it feeds on
I believe you are thinking of green-eyed monster, which is a symbol for jealousy.
One could be a metaphor, for example referring to jealousy as "a green-eyed monster".
If someone calls you a "green eyed monster" they are saying you are jealous. It's similar to the expression, "green with envy". Some people say this phrase comes from the Marvel Comic Book character, The Incredible Hulk, but it most likely originated from Shakespeare as he referred to "green eyed jealousy" in his play, The Merchant Of Venice; as well as "the green eyed monster" in Othello.
A green-eyed monster is a common symbol of jealousy. It is often depicted as a creature with green eyes to represent envy or jealousy.
The best idiom for jealousy is "the green-eyed monster." Saying this means that someone is jealous of something. You don't actually call the person a monster, though. You say "He was in the grips of the green-eyed monster," or "She felt the green-eyed monster taking over." It is as though jealousy is a separate thing from the person.
The term "green-eyed monster" is often used to refer to jealousy, but it doesn't have a specific name. The phrase is famously attributed to Shakespeare's play "Othello," where it symbolizes the destructive nature of jealousy. While it personifies jealousy, it doesn't imply that the monster itself has a distinct name.