To "look after" is to care for. It means to care for a small child.
It means that you "Take a look" or to look at something.
It is an introduction to your first impression of something.
I have not heard this idiom before. Perhaps you heard "Put to death" which means to kill.
This isn't an idiom. It means just what it sounds like - someone is looking for things by using their senses to find them.
"To be" is not an idiom - it's a verb.
Pest is not an idiom. It's a word.
It's not an idiom, it's a description. Go look in a mirror and close your mouth and you'll see what it means. It's someone who isn't talking.
This isn't an idiom because you can figure it out if you look up the word "pins." It is a SLANG term meaning legs, so you knocked him over.
The idiom "apple shiner" means the teacher's pet.
The meaning of the idiom in the pink of health means being in good health.
It's not an idiom - to cope means to deal with, or to handle
The idiom means impress someone is egg on