meander
Mates
major
matriarch, meaning female head of the family.
Actually, it starts and ends with "M", but you remove the first "M" and insert an "O" ANYWHERE in the word, not just replace "M" with "O"
Modernize is a word that starts with m and means to upgrade.
Moon walk
Make is a word that means to create and starts with "m".
Marvelous Or Modelesque (urban dictionary) Meaning having the look of a model.
my
mother, morning, modest, meaning, maize, mom, multiplication
A four letter word that starts with J and ends with M: jism.
methionylglutaminylarginyltyrosylglutamylseryllleucylpheny