General terms:
* Primate: This is the broadest term, as monkeys are primates.
* Ape: Some monkeys are apes, like the chimpanzee and gorilla.
* Simian: A more formal term for monkey.
Specific aspects:
* Troupe: A group of monkeys.
* Chatter: The sound of monkeys communicating.
* Swing: A monkey's movement through trees.
* Tail: A distinguishing feature of many monkeys.
* Fur: The covering of a monkey's body.
* Habitat: The natural environment where monkeys live.
Other related words:
* Monkey business: Mischief or playful behavior.
* Monkey wrench: A tool used for turning nuts and bolts, but also used metaphorically to describe something that disrupts a plan.
The best noun for you depends on the specific context you're looking for.