When a person is "banking on" something, it mean that they are depending on it to happen, and are fairly confident that it will happen.
"As deaf as a post" is an idiomatic phrase that means 'very or extremely deaf'.
An idiom is a phrase that has a figurative meaning different from its literal meaning, while an idiomatic expression is a specific phrase or sentence structure that is characteristic of a particular language or dialect. Idioms are a type of idiomatic expression, but not all idiomatic expressions are idioms.
It means corn-fed, country, unworldly, simple, naive, or unsophisticated.
The idiomatic phrase before another verb is spelled "supposed to", meaning should, intended to, or ought to.
If you are looking for the literal meaning, it means that something was electrically charged. If you mean the idiomatic or figurative meaning, it means that a situation was emotionally "charged" and volatile.
The meaning of the idiomatic expression, get a foothold in, is that you only need a small opening. This phrase is often used in business. One example of getting a foothold in would be getting an introduction to someone who works in a company that you would like to work in.
an idiomatic expression
You didn't say if you meant the phrase "in the dark" as the literal meaning or the idiomatic meaning. Literal: "When the moon sets, we will be in the dark." Idiom: "Bill is mad at me, but I am in the dark about the reason."
The question doesn't really make sense - idioms use words the same as any other phrase does. The words communicate meaning to others. The only difference between an idiom and another phrase is that the idiom has a meaning that is not literal and cannot readily be discerned by context.
That is the correct spelling of the idiomatic phrase "up to."
The idiomatic usage is not hyphenated. The term "used to" is a colloquial phrase meaning either - (adjective) accustomed to - (auxiliary verb) did previously, in the past
"You" is not an idiom. It is a pronoun.