magist-, master- +

1. A woman with whom a man has a usually long-term extramarital sexual relationship, often one in which he provides financial support.
2. A woman who owns or controls something.
3. Something that rules or controls something or someone; personified as a woman.
4. A woman who is highly skilled in a particular activity.

1. The person in charge of a post office or postal district.
2. The person responsible for the maintenance of a website and for being the contact point for information and complaints.
3. A computer e-mail program that distributes, forwards, and receives electronic mail.

1. A man who associates with or pays for sexual relations with prostitutes or a prostitute.
2. Someone who consorts with whores; a lecher or pander.
3. A pimp who procures whores for customers; usually, a man, who finds customers for a prostitute in return for a portion of the prostitute's earnings.