Definitions

minister (n.)
c. 1300, “man consecrated to service in the Christian Church, an ecclesiastic;” also “an agent acting for a superior, one who acts upon the authority of another,” from Old French menistre “servant, valet, member of a household staff, administrator, musician, minstrel” (12c.) and directly from Latin minister (genitive ministri) “inferior, servant, priest’s assistant” (in Medieval Latin, “priest”), from minus, minor “less,” hence “subordinate” (from PIE root *mei- (2) “small”) + comparative suffix *-teros. Formed on the model of magister (see master (n.)). Minister views a man as serving a church; pastor views him as caring for a church as a shepherd cares for sheep; clergyman views him as belonging to a certain class; divine is properly one learned in theology, a theologian; parson, formerly a respectful designation, is now little better than a jocular name for a clergyman; priest regards a man as appointed to offer sacrifice. [Century Dictionary, 1895] The political sense of “high officer of the state, person appointed by a sovereign or chief magistrate of a country as the responsible head of a department of the government” is attested from 1620s, from notion of “one who renders official service service to the crown.” From 1709 as “a diplomatic representative of a country abroad.” A minister without portfolio (1841, in a French context) has cabinet status but is not in charge of a specific department.

magistrate (n.)
late 14c., “a civil officer in charge of administering laws,” also “office or function of a magistrate,” from Old French magistrat, from Latin magistratus “a magistrate, public functionary,” originally “magisterial rank or office,” from magistrare “serve as a magistrate,” from magister “chief, director” (see master (n.)). From late 17c. often meaning “justice of the peace” or other minor officials having criminal jurisdiction.

magisterial (adj.)
1630s, “of or befitting to a master or teacher or one qualified to speak with authority,” from Medieval Latin magisterialis “of or pertaining to the office of magistrate, director, or teacher,” from Late Latin magisterius “having authority of a magistrate,” from magister “chief, director” (see master (n.)). By 17c. often with a suggestion of “arrogant, imperious, domineering.” Meaning “holding the office of a magistrate, proper to a magistrate” is from 1650s (see magistrate). Related: Magisterially.

master (n.)
late Old English mægester “a man having control or authority over a place; a teacher or tutor of children,” from Latin magister (n.) “chief, head, director, teacher” (source of Old French maistre, French maître, Spanish and Italian maestro, Portuguese mestre, Dutch meester, German Meister), contrastive adjective (“he who is greater”) from magis (adv.) “more,” from PIE *mag-yos-, comparative of root *meg- “great.” The form was influenced in Middle English by Old French cognate maistre. From late 12c. as “man eminently or perfectly skilled in something,” also “one who is chief teacher of another (in religion, philosophy, etc.), religious instructor, spiritual guide.” Sense of “master workman or craftsman, workman who is qualified to teach apprentices and carry on a trade on his own account” is from c. 1300. The meaning “one charged with the care, direction, oversight, and control of some office, business, etc.” is from mid-13c.; specifically as “official custodian of certain animals kept for sport” early 15c. (maister of þe herte houndes; the phrase master of the hounds is attested by 1708). As a title of the head or presiding officer of an institution, late 14c.; as “captain of a merchant vessel” early 14c. In the broadest sense, “one who has power to control, use, or dispose (of something or some quality) at will,” from mid-14c. Also from mid-14c. as “one who employs another or others in his service” (in which sense the correlative word was servant, man, or apprentice); also “owner of a living creature” (a dog, a horse, also, in ancient contexts a slave); paired with slave in the legal language of the American colonies by 1705 in Virginia.

mister
as a conventional title of courtesy before a man’s Christian name, mid-15c., unaccented variant of master (n.), but without its meaning. As a form of address when the man’s name is unknown (often with a tinge of rudeness), from 1760. The disappearance of master and mister, and the restricted and obsolescent use of sir, as an unaccompanied term of address, and the like facts with regard to mistress, Mrs., and madam, tend to deprive the English language of polite terms of address to strangers. Sir and madam or ma’am as direct terms of address are old-fashioned and obsolescent in ordinary speech, and mister and lady in this use are confined almost entirely to the lower classes. [Century Dictionary, 1895]

courteous (adj.)
c. 1300, curteis, “having elegant manners, well-bred, polite, urbane,” also “gracious, benevolent,” from Old French curteis (Modern French courtois) “having courtly bearing or manners,” from curt “court” (see court (n.)) + -eis, from Latin -ensis.

court (n.)
late 12c., “formal assembly held by a sovereign,” from Old French cort “king’s court; princely residence” (11c., Modern French cour), from Latin cortem, accusative of cors (earlier cohors) “enclosed yard,” and by extension (and perhaps by association with curia “sovereign’s assembly”), “those assembled in the yard; company, cohort,” from assimilated form of com “with, together” (see com-) + stem hort- related to hortus “garden, plot of ground” (from PIE root *gher- (1) “to grasp, enclose”). Both senses of the Latin word emerged in English. From the purely physical sense come “palace, residence of a sovereign” (c. 1200), “enclosed space connected with a building or buildings” (early 14c.), and the sporting sense “smooth, level plot of ground on which a ball game is played” (1510s, originally of tennis). Also “short arm of a public street, enclosed on three sides by buildings” (1680s), formerly noted for poverty or as business districts. From the notion of “surroundings of a sovereign in his regal state” (c. 1200) comes the legal meaning “a tribunal for judicial investigation” (c. 1300, early assemblies for justice were overseen by the sovereign personally), also “hall or chamber where justice is administered” (c. 1300). As an adjective, “pertaining to a court,” late 13c.