my (southern) wife refuses to believe the following have ever been used by human beings in a sentence but these are all fairly common to me and she thinks I'm making them up
Skerrick - meaning a small amount (he ate every skerrick
skeg - to have a look at (I'm off to have a skeg at....)
went for a burton - to fall over
There's some strange ones in Brazilian Portuguese, I don't know if my teacher was just joshing me but apparently "at night all cats are brown", and my favourite: "a dog bitten by a snake is afraid of sausages"