From glastwr (“milk diluted with water”) + -llyd (literally, "blue-watery").
glastwrllyd (feminine singular glastwrllyd, plural glastwrllyd, equative mor lastwrllyd, comparative mwy glastwrllyd, superlative mwyaf glastwrllyd)
Note: Certain mutated forms of some words can never occur in standard Welsh.All possible mutated forms are displayed for convenience.