Dutch

Dutch adjective:
When Britain was a maritime power ...Dutch people were giving tough competition so british people started introducing the Dutch adjective for something that is of low or demeaning.
Here are some of them

Dutch courage:
one who doesn't have any courage

Dutch widow:
A prostitute

Dutch auction:
A auction in which prices are going down

Dutch concert:
A poor concert

Dutch treat:
A treat where everybody pays for themselves only

Dutch metal:
A alternative low quality metal for gold.