It should be a close shave. Picture someone shaving their hair very close to the skin. This idiom means that you escaped something bad by a very small margin - as small as the width of a hair.
"You" is not an idiom. It is a pronoun.
to support
This expression means real and simple.
pleasant and easy....
It means to get married.
It means that is the essence of it. Similar to the expression 'in a nutshell'.
a mass where prayers are sung
i believe it means: to hope that...
Go nuts; crazy.
timid,coward
In this idiom, "He has a big head" means that the person is arrogant or conceited. It suggests that the person thinks highly of themselves and may not be humble.
stop doing what you're doing