The slangy verb welsh, meaning (1) to go back on a promise, or (2) to shirk one’s responsibilities (often with regard to gambling or debt), might be considered offensive to people from Wales. The origins of the word are unknown, but it’s no stretch to speculate that welsh could have begun as a derogatory term derived from a habit perceived to be common among Welsh people. In any case, it might be best to use the word cautiously, if at all.
AIG did not welsh or even have the chance to welsh on its credit, but the feds carted off 80 percent of the company anyway. [Washington Post]
[W]ith the state government accusing Canberra of trying to welsh on its promise to pay the money. [The Age]
The last really ”tough” budget, he says, was in 1993 when the Keating government increased indirect tax and welshed on some promised income tax cuts. [Sydney Morning Herald]