"For short" and "short for" mean a shortened form of a word, as an abbreviation or a contraction. For example, the nickname "Deedee" may be short for the Irish name "Deirdre."
It means an unscheduled short test in school.
In short supply means that there is not much of whatever it is.
It's not really an idiom. It means "what are you thinking about."
It is not an idiom, it means your nose is itching.
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
when you were in diapers when you were in short pants
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.