I'm not sure what fiction you mean. The word "fiction" is not an idiom -- it's a word and you can look in a dictionary to find it's meaning. There are too many idioms in works of fiction to name here. Click the related link to see some idioms.
an idiomatic expression
idiomatic expression
"You" is not an idiom. It is a pronoun.
Idiomatic expression
Not trustworthy
humbly
Jasjs
Give me 1 example of idiomatic expression
This expression means real and simple.
to support
yes it is
babysitting