This is a polite term for being pregnant. It's more common among older people. Younger people might say "knocked up" or "preggers." The idiom refers to the idea that a pregnant woman is going to produce a family soon.
An idiom usually is a sentence, or part of one. It certainly can be used as part of a sentence. The way to tell if it's an idiom is if it makes sense the way it's literally written.
The idiom or expression, where there is will there is way means that there is a way around everything. It also means nothing is impossible.
It is just an exaggerated way of saying something happens quite often - it is hyperbole, not an idiom.
This is not an idiom that I have ever heard. Perhaps you mean an arm AND a leg, which is an exaggerated way of saying something is really expensive.
It's not an idiom because you can figure it out. It's a sarcastic way of saying something is not clear - it's as dark as mud.
judging someone by the way they look, not who they are as a person
The idiom refers to the tossing or throwing of a coin to make a choice. It means that the choice of correct answer or way forward is as random as the toss of a coin.
An idiom misuse is to use and idiom in a wrong way that doesn't make sense.
It means to feel that there is no way to go on and you just want to give up.
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.