With as many entries as there were for F, it's a damned good thing there's so few G words of any note in Old Norse. Oh wait.... And yes, I understand this is getting posted a day late. I figured if I posted it right after the F post nobody would have a chance to read that one and Sunday was a "break" day anyway. I did forget it was a holiday though, so Happy Eostre, Ostara, Easter, Passover, or whatever it is, if anything, you celebrate this weekend.
G is for Galðr, which is a type of magic involving words and/or runes, they may be written, spoken or chanted, but they must be words. This is what I think of when I think of a traditional Magic-User in an Old Norse or Viking context. There are spells that have verbal, somatic and material components, in Galðr you have Galðrbók (Book of Magic, Spell Book), Galðrastafr (Magic Staff) and Galðravél (Magical Device). This is a type of magic used by both men and women, as opposed to seiðr, which was considered to be a woman's magic (despite Odin's having learned it from Freyja).
G is for Gullinborsti, which means "Golden-Bristle", it is the name of Frey's boar that was made by the Svartálfar (or Dwarf) brothers Brokkr and Sindri. He either rides it like a horse or has it pull a cart.
G is for Garð, which is a word meaning "enclosure", but really means something more akin to "protected-space" or "inside the walls". The most famous Garðs are Asgarð and Midgarð, the realms of the Aesir and of men respectively, but the term was used for other places than just worlds. The Norsemen referred to Constantinople as Mikligarð (the Great Enclosure, or simply, the great city), and when gathering for a truce during war or at a temple it was sometimes referred to as a "friðgarð" or an "enclosure of peace", yes, I started using the eth today instead of constantly using a th, otherwise the sound of the letter will get mixed up with the other th sound.
G is for Garmr, the "Hound of Hel" who is chained in a cave called Gnípahellir, which is either the entrance to Hel's realm, sometimes called Helheim apparently just to keep the ruler and the place clear; or it is the entrance to Niflheim, which is a much nastier place under Hel's dominion. Either way, he is referred to once as "The best of Hounds", then it is revealed that he will break his bonds at Ragnarok, seek out and kill the God Tyr. Between this and the use of his name in kennings as a word for destructive forces, some scholars believe that Garm may just be another name for Fenrir, which I guess means that Fenrir's body count at Ragnarok is better than anyone else's because he takes down to major Gods of the Aesir.
G is for Gefjon, a Goddess of the Aesir with two contradictory background stories, in one she is said to be a virgin Goddess and really not terribly interesting; in the other it is said that she was a prostitute that sold herself to the King of Sweden. As payment for her services rendered he offered her as much land as she could plow with four oxen. She got four huge oxen, which were actually her sons with a Jötunn, and plowed away from Sweden a huge chunk of land into the sea, which became the island of Sjælland, which became Denmark's main island and where the city of Copenhagen is located. She is also associated as an ancestress of the Danish kings of old, the Skjöldungs, who are known in Old English as the Scyldingas.
G is for Geri, the other Wolf of Odin.
G is for Gná, a goddess of the Aesir, who is primarily known as Frigg's go-fer. She has a magic horse that can run over air and water. She runs a lot of errands.
G is for Gullveig, a Goddess of the Vanir, a witch. Her attempted execution at the hands of the Aesir caused the war between the Aesir and the Vanir. She may actually be the Goddess Freyja.
G is for Gungnir, Odin's Spear, made by the sons of Ívaldi. The D&D books make a lot out about the powers of this spear, but the lore doesn't really attest to much about it except to say that "it is so well balanced that it can strike any target, no matter the skill of the wielder". It may well be the spear that pierces Odin as he hangs on the tree for nine nights as a sacrifice to gain knowledge of the runes, and it is attested that the act of throwing a spear over the enemy army makes them,and their goods, a sacrifice to Odin; therefore you may take no booty and any prisoners must be sacrificed.
G is for Glíma, which is the Old Norse word for wrestling, but is also a modern Icelandic sport that I became aware of when I was writing up prestige classes for my 3e Norse campaign. Glíma has a number of interesting things about it that make it stand out from standard wrestling or really any other type of ethnic wrestling I have ever seen. Oddly, it reminds me most of Mongolian wrestling. Anyway, being a bad-ass wrestler is always a good thing, and more so in a scoiety that celebrates strength and martial manliness like the Norsemen. Slightly out of period, but Beowulf wrestled Grendel and tore his arm off. That's a totally Viking style thing to do.
G is for Goði, in Iceland they were a combination of chieftain and priest, a secular and religious leader. The plural is Goðar, their domain is called a Goðorð. The feminine version of the title is Gyðja. It is probable that in continental Scandinavia there were temple based Goðar and that in Iceland the traditional duty of Jarls devolved into the duties of Goðar. In modern Germanic Heathenry, particularly Asatru, this is often a term used for the priesthood.