* Gibbous Moon: A phase of the moon where more than half of the moon's visible surface is illuminated by the sun.
* Monkey: A primate, a type of mammal.
They are from different categories, have different properties, and serve different purposes. There might be a playful connection to be made if we wanted to get creative. For example, we could say that a gibbous moon looks like a monkey's face when it's partially illuminated, but that's purely imaginative.
Could you tell me what made you think they might be alike? Perhaps there's a specific observation or idea you'd like to discuss.