Masterful. / Main, principal or predominant. / Highly skilled. / Original.

(intransitive) To be a master. / (transitive) To become the master of; to subject to one's will, control, or authority; to conquer; to overpower; to subdue.

(nautical, in combination) A vessel having a specified number of masts.

The matter or thought presented for consideration in some statement or discussion; that which is made the object of thought or study.

Mode of action; way of performing or doing anything / Characteristic mode of acting or behaving; bearing / One's customary method of acting; habit. / good, polite behaviour

The finger on which a wedding ring is placed; the ring finger.

(idiomatic) An unconsummated marriage.

(sometimes attributive) A system for conducting elections in which voters receive and return ballots via the mail

(uncountable, networking) Email (the system). / (countable, dated) An email.

(nautical) A tool somewhat like a chisel with a groove in it, used by caulkers of ships to finish the seams after the oakum has been driven in.