Incessant and continuous is not an idiom and it is not a happy phrase. Incessant, continuous works; or inverted into continuous, incessant; or separated with another idea e.g. continuous and seemingly incessant.
its an idiom but i guess it could be considered a phrase too in a way?
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
to do nothing nothing to do
Yes it is.
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.