The problem is that the english term "master" does not have a direct equivalent that is universal across asian languages. There are many terms that can be used, but all of the terms I know have meanings that do not correspond to "master." Plus, each buddhist tradition has their own terms for levels of attainment, and those terms are not used consistently from group to group.
A term I am interested in as a possible translation but do not know enough about is 主 or 主宰.
"Do not worry; cultivate the habit of being happy." - Samael Aun Weor