Idioms and Plagiarism

[tchiko95]

Hi everyone,

I have a simple question if the post on site contain a list of idioms, these idioms are common we found them in different books, sites about foreign language ... are there considered plagiarism in SEO and AdSense?

Thank's for your help

[Nizam18]

researching idioms may be useful for:

Getting more keyword and content ideas;
Gaining a deeper understanding of the topical language;
Finding more catchy domain names ideas; etc

[briggsn]

I would also like the answer to this as I am confused whether to use idioms while writing or not.