* "Her clumsiness was legendary, always tripping over her own feet and dropping things." (This sentence uses "clumsiness" as a noun to describe a person's tendency to be clumsy.)
* "The waiter's clumsiness resulted in a spilled drink all over the customer's white shirt." (This sentence uses "clumsiness" as a noun to explain the cause of a situation.)
* "He apologized for his clumsiness, but the vase was already broken." (This sentence uses "clumsiness" as a noun to acknowledge the cause of an accident.)
* "Despite her clumsiness, she managed to win the dance competition." (This sentence uses "clumsiness" as a noun to highlight a contrast.)
You can also use "clumsy" as an adjective:
* "He was a clumsy dancer, but he had a lot of fun."
* "The clumsy dog knocked over the flowerpot."
The best way to use "clumsiness" or "clumsy" will depend on the context of your sentence.