(welsh, welch) v.t. & v.i. Slang
1. To cheat by failing to pay a bet or debt.
2. To avoid fulfilling (an obligation). Also spelled welch. [? Back formation <welsher, prob. <Welsher a Welshman, with ref. to supposed national traits]

(welsh, welch) adjective
Pertaining to Wales, its people, or their language.
—noun
1. The natives of Wales, a people of Celtic stock: with the: also called Cymry.
2. The language of Wales, belonging to the Brythonic or Cymric group of the Celtic subfamily of Indo–European languages: also called Cymric. Also spelled Welch. [OE Welisc <wealh a foreigner (one not of Saxon origin)]
—Welsh′·man noun