An expression in the usage of a language that is peculiar to itself either in having a meaning that cannot be derived from the conjoined meanings of its elements or in its grammatically atypical use of words.
make a silk purse out of a sow's ear
to create something valuable out of something of no value
You cannot make a silk purse out of a sow's ear and the woman is not a good singer and will probably never sing in the choir.
List of common idioms, their meanings and examples of their usage in sentences
The language peculiar to a people or to a district, community, or class