Not really. The term "key" can also mean the most important thing or the thing that leads to other things. The term means that something is either the most important part of you, or that it will lead to other important facts about you.
No, the phrase "drunk with pleasure" is not considered an idiom. An idiom is a phrase that has a figurative meaning different from its literal meaning. In this case, "drunk with pleasure" is meant to be taken literally, describing a state of intense enjoyment rather than actual intoxication.
Yes
Can you figure out the meaning by defining the terms? Yes, so it's a phrase instead of an idiom.
The phrase "laid eyes on" is an idiom.
An idiom is a phrase that doesn't make any sense unless you know the idiomatic definition. This phrase means exactly what it looks like, so it's not an idiom.
An idiom is a phrase that doesn't make any sense unless you know the definition. This phrase makes perfect sense, so it is not an idiom. The room became quiet.
Stuck in a rut is a phrase, but I am not sure if an idiom is the same thing as a phrase. You may be thinking of a cliche and "stuck in a RUT" is a cliche. "Stuck in a road" is neither cliche nor idiom.
idiom
yes
Yes it is.
to do nothing nothing to do
A phrase unique to a particular language is called an "idiom." Idioms often have meanings that cannot be derived from the individual words used in the phrase.