Idioms using nationalities and countries

Mexican standoff = a situation in which people on opposite sides threaten each other but neither tries to come to an agreement.

Itʼs all Greek to me = I cannot understand it.

To take French leave is to leave a gathering without saying goodbye or without permission.

If something has more holes than a Swiss cheese, it has a lot of problems; there are many things wrong with it. It is incomplete or lacks important components.

Young Turk is a young person who wants great changes to take place in the established political system. Actually, the Young Turks (Jöntürkler) were politicians who fought against the authoritarian regime in late 19th and early 20th-century Ottoman Empire. They managed to rise to power and establish a constitutional government. They carried out progressive administrative reforms, promoted industrialisation and secularisation. Unfortunately, their efforts turned out to be futile owing to the Ottoman Empire’s entry into the First World War and subsequent defeat.

The phrase “Scotch mist” is used humorously to refer to something that is hard to find or doesnʼt exist — something imagined.

Dutch treat is an entertainment, meal, etc, where each person pays for himself or herself.

If there is a period of warmer weather in late autumn, it is an Indian summer.

Slow boat to China. This idiom is used to describe something that is very slow and takes a long time.

A person who talks for England, talks a lot.

Sources: https://dictionary.cambridge.org

https://www.oxfordlearnersdictionaries.com

https://www.collinsdictionary.com

https://www.macmillandictionary.com

https://www.merriam-webster.com