You're only as old as you feel.
feeling blue
feeling under the weather
be over the moon, be in seventh heaven, be as happy as the day is long
be down in the dumps
sense experience suffer under go be aware of think believe consider
savvy, brainy
Some words that describe space are:vastvoidcryptic
Not always. Sometimes idioms are just phrases.
Try this question for examples of idioms.
There are 25 idioms for police. Some of these are a steal, cat burglar, on the case and on the lam.
feeling under the weather
There are many idioms and phrases for 'on the back burner'. Some idioms and phrases for 'on the back burner' include 'pushing aside' and 'procrastinating'.
One reason why some idioms are confusing because the way the sentences are worded
"Idioms for Being Afraid", "Idioms for Being Angry", "Idioms for Being Happy" are some examples of idioms found in the book "Found" by Margaret Peterson Haddix.
There isn't one. I think you heard it wrong. You may be thinking of "feeling blue" or "being blue," which means feeling sad or depressed.
Here is a link to some idioms. You can pick the "non-common" ones for yourself -- some people have heard certain idioms a lot and others have not heard the same ones, so you'll need to decide that part.
Some websites that have idioms written in them include The Free Dictionary, Cambridge Dictionary, and Phrases.com. These sites provide definitions and examples of idioms to help users understand their meanings and usage in context.
savvy, brainy
The best place is to go on your search engine and type in "list idioms" You can also look at this question for some examples.
Nostalogic
cry unclemonkey's uncle