1. To cheat or fail to keep a promise: This is the most common and negative meaning of the word "welsh". It's often used in the phrase "to welsh on a bet" or "to welsh on a deal."
2. To be from Wales: This meaning is less common, and it's generally considered harmless. However, the first meaning is so ingrained in the language that it's possible to be perceived as offensive if you use "welsh" to refer to someone's nationality without being careful.
The Origin of the Offensive Meaning:
The origin of the negative meaning is unclear, but it's likely connected to historical stereotypes about the Welsh. Some theories suggest it originated from the fact that some Welsh people were employed as laborers in England and were sometimes accused of being dishonest. Others suggest it's connected to a historical event where the English monarch broke a promise to the Welsh.
In summary: While "welsh" can refer to being from Wales, its most common meaning is a negative one that implies dishonesty and broken promises. It's important to be aware of this meaning and avoid using it in a way that could be offensive.