madfall (Welsh) comes from Welsh mabddall, from Welsh mab, from Old Welsh map, from Proto-Brythonic mab, from Proto-Celtic makʷos, from Proto-Indo-European mh₂ḱwos, from Proto-Indo-European meh₂ḱ- — to raise, increase; long.
madfall (Welsh): lizard; slowworm, blindworm; newt