As a verb:
* The old man grumbled about the noisy teenagers on the bus.
* My stomach grumbled with hunger after a long day of hiking.
* She grumbled under her breath about the unfairness of it all.
As a noun:
* The teacher heard a grumble of disapproval from the back of the classroom.
* There was a grumble in the air about the new policy.
* The grumble of distant thunder grew louder.
In a figurative sense:
* The engine grumbled to life after a few coughs.
* The ancient city grumbled with secrets.
* The news of the scandal caused a grumble of discontent among the employees.