Nothing. I think you may mean "mend fences," which literally means to repair or fix the broken spots in a fence. Used as an idiom, it would mean to fix or repair a "broken" relationship by apologizing, compromising, and communicating.
It can be literally repairing breaks or weak spots in a fence, or it can be an idiom for repairing a "broken" friendship or other relationship.
It is not an idiom, it means your nose is itching.
It's not really an idiom. It means "what are you thinking about."
RFP is not an idiom. It's an abbreviation.
"Sieve" is not an idiom. See the related link.
It's not an idiom. It means the tip of your nostril.
idiom means expression like a page in a book
The idiom a slap on the wrist refers to a trivial punishment.
This is not an idiom. It is a measurement. $100,000 is how you write it in numbers.
Simply its mean a bully.
The idiom your blood is boiling usually means that you are mad/furious.
When someone mentions fences in baseball they are talking about the outfield wall between the foul lines.