Bynames were very common in medieval Scandinavia and Iceland. This is a list of some of the bynames found in Heimskringla, the historic (in a wide sense) work by Snorri Sturluson, a 13th century Icelandic writer and poet, maybe more known for his Edda. It is in no way complete, and a much more comprehensive list of Norse bynames, in Danish, can be found in Finnur Jónsson's Tilnavne i den islandske oldlitteratur, Copenhagen 1908.
The names are given in their Old Norse form and the meaning of them is taken from the commentary in Snorre Sturlasson, Nordiska kungasagor, volume 1-3, Fabel, Stockholm, 1992-1994, translated to Swedish by Karl G. Johansson, professor of Old Norse at the University of Oslo, Norway. Note that his interpretations do not always concur with Jónsson's. Unless noted these are men's bynames, which is to be expected, given the source.
Since the bynames were used in the stories to show which of all men with the same name the author meant they had to be well known to the intended listeners. Some of them were, however, not used by the persons themselves, and some of them would probably have been dangerous to use in front of them. Names like Ketlingr, kitten, or Mørnefs, fat nose were not intended to be flattering. Ynglinga saga Kraki: pole. Indicating a tall and thin person. Ylfingr: drawn from ”ulv”, which means wolf, so somehow connected to the wolf. Flettir: the quick, brisk etc Saga Hálfdanar svarta Skálk: servant, or rogue, joker Hjørtur: deer, a man who runs fast. Orm i auga: ”snake in the eye”, someone with a cold gaze. Haralds saga hins hárfagra Klofi: He who splits. Glumra: rumble, noise, possibly the sound of weapons in battle. Skirja: Cow. Lúfa: thick hair, the word means a kind of cap. Rise: Giant or Bastard, in the original sense. Háleggr: He with the long legs. Skurfa: Scab, the one you get on a healing wound Tota/toti: Mouth Mostrstøng: The thin one from the place ”Moster”, this one belonged to a woman. Sagan af Haraldi konungi gráfeld ok Hákoni jarli Slefa: He who drools or slurs. Skreyja: the frail, decrepit Askmaðr: viking, a seafarer. Saga Ólafs Tryggvasonar Klypp: a man of short, compact build. Vandræðaskáld: the unstable or inconsistent skald, i.e poet. Gellir: He who bellows. Kúlu: hump, hunchback Klakk-: He who avenges and causes pain Lyrgja: the drowsy Karkr: It could either mean thick, uneven tree bark or come from the verb ”karkla”, which means to cackle. Dyrðill: the prized one Skjálg: the squint-eyed Sýr: sow Lygru: The fair one Veili: The sickly one Eisli: He who howls Snákr: The common European adder/viper Smetta: He who sneaks. Sagan af Haraldi harðráða Drengi/drengr: the manly one. Snillingr: A brave man Skarða: It means cut, and may refer to a cleft palate. Ulfálda: camel Urarhorn: The horn of the aurochs. Geysa: the witty, but also the irritable, may indicate a changeable temper. Hímaldi: drone, sluggish person Saga Ólafs kyrra Hein: whet stone brynsten Kyrra: the quiet, calm one Saga Magnús konungs berfœtts Fletti: Probably means the plunderer. Prúði: The fine, grand, handsome one Digri: The big one Saga Sigurðar jórsalafara, Eysteins ok Ólafs Skvaldri: The talkative one. Kesju: Spear Smørbalte: Butter bear. Húkr: The squatting one, bending down. Grábarð: Greybeard. Flipr: Could mean hanging lip, but it is unsure Saga Inga Haraldssonar ok brœðra hans Birtingi: Trout Balli: The strong or violent one Hvinantorði: unsure, but may mean”whining dung”. Hardly flattering. Pungælter: He who prepares leather for purses. Skjappa: Bushel Glæserófu: A not so nice name used about a vain person, meaning “shining tail” Rangi: The bent one Kauðu: Hen Smyril: Merlin (the bird) Svipti: unsure, but possibly from the verb ”svipta”, which means to throw. Fægir: He who cleans or polishes Dynta: The conceited one Sturla: Violent, eager for combat. Hrúga: Pile or lump, probably referring to a person’s hape or build. Hroði: The one who is eager for combat. Sneis: Stick Dengir: He who strikes. Skálpr: Scabbard. Trafala: The troublesome one. Sætu: Woman who stays at home when her husband has left the country. Standala: Someone with an erect posture and manner of walking. Mørnefs: fat nose Hølðr: a free man Sagan af Hákoni herðibreið Skaufuskalla: The bald one with a few strands of hair. Óða: The wild one. Klíningr: Butter Úskeynd: The shieldless Jalda: Mare Skeggja: The bearded one. This one is found as the byname of a woman with magical powers. Hikri: The doubting Saga Magnús konungs Erlingssonar Kutiza: Unsure, but may mean cow’s teat. Sipill: He who slurps, may refer to drunkeness. Kunta: Cunt. Yes, it was used as a byname for someone, maybe not to their face though. Hjúpa: Cloak Kæna: A kind of boat Dryllr: The stout, sturdy one. Heiðafylja: Mare Rusli: The big one. Kúfungr: Snail Meyla: The woman-like, used for a handsome man of slim build. Ketlingr: Kitten.