That's not really an "idiom."
Cats are animals.
Cats lick themselves.
In the process of licking themselves they often swallow a certain amount of fur.
This hair gets balled up in their stomachs, and sometimes they'll cough (actually, it's more like "vomit") one back up.
The product of this is a "cat's coughed up fur ball". Like I said ... not really an idiom.
"Get on the ball and finish" is an idiom of "try harder" and "make an effort". Example: Sam really needs to get on the ball and finish his homework!
It's a sports reference. If you drop the ball, you have made a mistake and not done what you were supposed to do on your turn, or when the project was in your hands.
If someone says that something or someone else is "a ball of fire," it means that they are really talented and quickly rising in their field.
It's a sports idiom. When the ball comes into play, it is on the field and in the hands of an athlete. When something comes into play, it is in action in whatever situation is being discussed.
"On the ball" is a sports reference. It means that you are in control of the ball, so the idiom means to have things well in hand, to have anticipated all obstacles and be in control and a little ahead of things.
It's not really an idiom. It means "what are you thinking about."
RFP is not an idiom. It's an abbreviation.
It is not an idiom, it means your nose is itching.
It's not an idiom. It means the tip of your nostril.
idiom means expression like a page in a book
"Sieve" is not an idiom. See the related link.
This is not an idiom. It is a measurement. $100,000 is how you write it in numbers.