Where does “amrwt” come from?

amrwt (Middle Welsh) comes from Proto-Celtic an-, from Proto-Indo-European n̥-, from Proto-Indo-European ne — not.

Ancestry of “amrwt”, step by step

StepLanguageWordMeaning
1Proto-Celtican-un-, not
2Proto-Indo-Europeann̥-not, un-
3Proto-Indo-Europeannenot
Every word from Proto-Indo-European ne →Every word from Proto-Indo-European n̥- →Every word from Proto-Celtic an- →