scwelsh Share definition Flag a scwelsh is a person with scottish and welsh blood in them. Can also be called a mongrel "williams is a scwelsh because his grandad is scotish and his nanny is welsh" "aye it tis true" scwelsh by shauny the lamb March 31, 2007 0 0 Get merch Get the scwelsh mug. Buy Now — $32.95 See more merch