Where does “mugir” come from?

mugir (Old Portuguese) comes from Latin mugire, from Latin mugio, from Proto-Indo-European mūg-.

Ancestry of “mugir”, step by step

StepLanguageWordMeaning
1Latinmugirepresent active infinitive of mūgiō; to bellow
2LatinmugioI moo, low, bellow; I roar, rumble, bray, groan
3Proto-Indo-Europeanmūg-—
Every word from Proto-Indo-European mūg- →Every word from Latin mugio →Every word from Latin mugire →
mugir — Etymology, Origin & Word History | Etymology Explorer