Headmaster Albus Dumbledore: His first name is from the Latin word alba, "white." His last name, according to Rowling interviews, is Old English for "bumblebee." In color symbolism, white often stands for purity, so the headmaster's name suggests honor and a hard-working nature ("busy as a bee").
Professor Binns: A bin is a large storage container. A dustbin is British English for a garbage can. This boring professor could be described as a ghostly storage for information that many Hogwarts students view as rubbish.
Headmaster Armando Dippet: Armando is from the name Armand, "of the army." Dippet is not a word in English, but dip has many meanings, including: (1) to put something into something else, often a liquid; (2) to take something out of something, as in dipping out water; (3) to lower and raise something; (4) a fool.
Argus Filch: In Greek mythology, Argus the All-Seeing was a man with 100 eyes on his body, who gained a reputation as a great watchman. The goddess Hera asked him to watch a priestess, Io, who had been turned into a heifer, or young cow, because she had fallen in love with Hera's husband, Zeus. However, Hermes, messenger of the gods, tricked him by telling him long, boring stories. All those eyes closed in sleep, and Hermes stole away Io. Filch is an informal word that means to secretly steal items of little value.
Professor Filius Flitwick: Filius is Latin for "son of." Flitwick is a town in England but also suggests movement of a wand. To flit is to move quickly from location to another. A wick is a loosely woven strand of fabric or fibers, often used in a candle or oil lamp. A wick has a similar shape to a stick (wand).
Rubeus Hagrid: Rubeus, possibly from the Latin rubinus, "red." Also possibly from Hagrid Rubes, "Giant of the Jewels." He was a kind giant in ancient Greek mythology. (Hagrid is a nice, generous man.) Zeus, chief of the gods, framed him for murder. (Hagrid and Aragog were framed for deaths of Hogwarts students.) Zeus banished him from Mount Olympus, home of the gods, but allowed him to take care of the animals. (Headmaster Dippet expelled him from Hogwarts, but Dumbledore convinced him to keep Hagrid on as head gamekeeper.) Hagrid also may nean "hung over," as from alcohol. Hagride is a verb that means "to torment."
Madam Hooch: Hooch is (1) U.S. slang for hard liquor, especially whiskey or illegal (bootleg) alcohol. Hooch is from hoochihoo, a liquor distilled by the Hutsnuwu Indians. (2) It also can be slang for marijuana. (3) Among American soldiers fighting in Vietnam in the 1960s and '70s, it was slang for a hut, particularly one in a rural native village. Hooch's possible first name, Xiomara, may be either Aztec or from another Latin American Indian nation. You see Xiomara used as a first name for Latin American females.
Gilderoy Lockhart: "Gilde" is from the word "gilded," or decorated with a thin layer of gold. "Roy" is from the French word roi, or king. Lockhart is a Scottish name. It contains the words "lock" and "hart" (heart). The Clan Lockhart's slogan is "I open locked hearts." So he is a gilded, golden-haired king whose big smile and friendly ways unlocks hearts (especially girls'). Lockhart also is a town near Wagga Wagga, Australia, which explains the Wagga Wagga Werewolf.
Professor Kettleburn: Humorous name suggesting either a container that got burned, or an injury gotten from one. A cauldron is a type of metal kettle.
Professor Minerva McGonagall: Minerva was the Roman goddess of wisdom and war. Her pet was an owl, like Athene, who was her equivalent in Greek mythology. The name Minerva also means "wise." The Scottish name McGonagall (or McGonigle, McGonegal) is from the Celtic name Conegal, meaning "the bravest," plus Mc, or "son of."
Alastor Moody: or Alastair, is from the name Alexander, "protector of mankind" (good name for an Auror). Moody means temperamental or tending to quickly change moods.
Madam Irma Pince: Irma is from German irmen for "whole" or "complete." Pince is from pince-nez, a pair of glasses with no side ear temples, but just lenses and their frames. They clip on the bridge of the nose. Pince-nez is "pinch (the) nose" in French. This type of eyeglasses is sometimes seen on stern or bookish people in literature, movies, TV, etc.
Madam Poppy Pomfrey: The poppy, genus Papaver, has served both decorative and medicinal purposes. The opium poppy, Papaver somniferus, is the most notorius species, producing legal and illegal drugs. It is used to make the legal painkillers codeine and morphine, but also produces opium and heroin. The non-addictive poppy seeds are commonly used in baking. Pomfrey is a contraction of the city of Pontrefact, North Yorkshire, England. Pomfrey cakes are small, sweet lozenges made from the roots of the licorice plant. Licorice also has been a medicinal ingredient for hundreds of years.
Professor Quirrell: May be from the word squirrel, for a group of nervous, nut-eating rodents that live in trees. The professor was a scared, shaky man who behaved a lot like one, later an act to cover up his allegiance to Voldemort. The Diagon Alley extension of the Harry Potter Trading Card Game lists Quirrell's first name as Quirinus. Several Roman Catholic martyrs bore this name. Quirinus also was the name of a Sabine war god worshipped by the ancient Romans. It may be derived from the world "spear" in the Sabine language, and from the Latin corvirium, or "assembly of men."
Professor Sinistra: The Latin sinister meant "on the left," or more often, "unlucky." Something that is sinister in Modern English means it is evil or suggestive of evil. The left side was often associated with evil or bad luck in Roman and other ancient cultures.
Professor Severus Snape: Severus was the name of several ancient Roman emperors and later, early saints. Severus is the Latin word for "strict" or "severe," which the professor truly is. Snape also a town in England. It also is a shipbuilding term. It means to bevel the end of a piece of wood, or cut it at a sloping angle, so it fits against an inclined surface.
Professor Sprout: Her very appropriate plant-oriented name means to (1) spring up and grow; (2) to send out new growth.
Professor Sibyll Trelawney: Sibyl was a priestess in ancient Greek mythology. A sibyl (one "l") is a woman who could look into the future. Often sibyls came in groups of 10 and were found in the Greek, Egyptian and Babylonian cultures. A sibyl also can be any female prophet. The name is from the Latin sibylla, seer. Trelawney is an English name meaning "for God."
Professor Vector: A vector is a mathematical term for either (1) a one-dimensional array or (2) a quantity that has a magnitude and a direction, often represented by a line segment. Vector teaches Arithmancy, which is fortune-telling with number values.