A house of cards means you have a situation that is not planned well and could fail or collapse easily.
A literal house of cards is when you use playing cards to make a house or tower. However, it is very hard to balance, and if one card near the bottom gets moved, the whole thing tumbles down.
Often, people have circumstances in their lives set up that way. There might be a number of wrong things in the person's life. All it takes is for one more thing to go wrong or for some secret to be revealed, and their entire life comes apart.
"To be" is not an idiom - it's a verb.
Literal meaning is in a fine plumage, the idiom means well dressed; of an excellent appearance
Pest is not an idiom. It's a word.
The idiom "apple shiner" means the teacher's pet.
The meaning of the idiom in the pink of health means being in good health.
putting all your cards in the table
"To be" is not an idiom - it's a verb.
Literal meaning is in a fine plumage, the idiom means well dressed; of an excellent appearance
Pest is not an idiom. It's a word.
The idiom "apple shiner" means the teacher's pet.
in the cards
The meaning of the idiom in the pink of health means being in good health.
It means to tidy up, put everything in its place and make things look neat.
The idiom means impress someone is egg on
It's not an idiom - to cope means to deal with, or to handle
"Old hand" is an idiom meaning having lots of experience.
It is not an idiom. It is an expression. The difference is that an idiom's meaning cannot be derived from the meaning of its individual words. In the expression wolfing down food, the meaning is clearly derived from the meaning of the words, and people have been saying it for hundreds of years.