more majorum (L.), after the manner of our ancestors.
more suo (L.), in his own way.
motivé (Fr.), supported by a statement of reasons.
motu proprio (L.), of his own accord.
muet comme un poisson (Fr.), mute as a fish.
multum in parvo (L.), much in little.
multum non multa (L.), much, not many things.
mutatis mutandis (L.), with necessary changes.
mutato nomine (L.), the name being changed.
mutuus consensus (L.), mutual consent.