15 Basic Words That Are Etymological Mysteries

All words had to start somewhere. Through the careful work of historical linguists and lexicographers, we can usually trace a word, if not to its ultimate origin, at least pretty far back in time. We know that the word water, for example, goes back to an old Germanic source by comparing it with words from other Germanic languages: Dutch water, German Wasser, Old Icelandic vatr. We know the word fruit came to English from French because we first have evidence of its use during the period when the French Normans ruled England.

Sometimes, after much searching and analyzing, no satisfying origin explanation can be found. This is not so surprising for slangy or risqué words—if they aren’t the type of words that would be written down, it will be hard to find early sources for them—but there are a few pretty basic, run-of-the-mill words that have defied the best efforts of etymologists. As Anatoly Liberman of the Oxford English Dictionary says, “the progress of etymology consists as much in discovering words’ true origins as in discarding wrong and dubious conjecture. One of its bitter triumphs is the ability to say ‘origin unknown.’”

Here are 15 basic English words that have remained etymological mysteries.

1. Dog

English has the word hound, which is clearly related to other Germanic words like Hund, and the word cur, which is related to other Germanic words for growling. But the most common term is dog, which looks nothing like any other language. It seems related to similar untraceable English words pig, hog, stag, and the wig of earwig. Are they too ancient to trace? Were they originally childish nicknames or slang? Many theories have been explored, but the answer has not been settled.

2. Bad

What could more basic than bad and good? We know that good is cognate with many other languages, from Gothic to Old Saxon to Dutch, and evil is from a Germanic root, but bad is on its own. Its earliest uses referred to food that had gone bad.

3. Big

Big is a pretty basic concept, but it was not the word of choice in the Old English period (when the word was mickle or great) and only shows up from the 14th century. Was it borrowed from a Scandinavian word for a rich, powerful man? Did it come from someone’s name? The status remains “origin unknown.”

4. Girl

Maiden is from a Germanic root, and damsel is from a French one, but where does girl come from? Perhaps an old Germanic word for dress or a borrowing from another word for child. We don’t know, but it used to be used for boys too. In the 1300s and 1400s, gurles or gyrles were children of either sex, and if you wanted to specifically refer to a boy child you could say “knave girl.”

5. Boy

Knave goes back to Old English from a Germanic root, but boy only shows up in the Late Middle Ages and in its earliest uses was an insulting term for slave, rogue, or wretch. Did it come from an old French word for “person in chains”? A Dutch word meaning messenger? It’s unclear, but the OED says that for words like girl, boy, lass, and lad, “possibly most of them arose as jocular transferred uses of words that had originally a different meaning.”

6. Donkey

While the word ass can be connected to Gothic, Latin, Celtic, and Semitic languages, donkey is a mystery. Etymologically speaking, it’s a relative newcomer, first appearing in slang dictionaries in the 18th century. It might come from the adjective dun, meaning dingy brown, or the name Duncan. Apparently, it used to rhyme with monkey.

7. Bird

The more common word in Old English was fugel, which can be traced back to an old Germanic root for flying (and which gives us the current word fowl), but somehow bird won out. Bird was originally spelled brid, which gave the idea that perhaps it was related to brood, but what we know about historical sound change rules makes that unlikely.

8. Surf

Surf, as a noun for the breaking waves, first appears in the 17th century. It might be a blend of an old word suff, for the inrush of the sea, with surge. Or it could be borrowed from an Indian language.

9. Fuss

Fuss shows up in the early 1700s as a way to describe a showy, out-of-proportion commotion. It could be from an imitation of a rustling or blowing sound, another English word like force, or a word from another language.

10. Blight

Blight certainly looks like an old English word from an old Germanic source, with its gh spelling, but it’s unattested until the 17th century and seems to have begun as a term among gardeners.

11. Log

There is an Old Germanic root laeg, related to lie, that became the word for a felled tree in Old Norse, but etymologists have ruled out this source because due to sound change rules, that would have ended up pronounced low in English. It may have been borrowed from a later stage of a Scandinavian language because of the timber trade, but it could also be from an attempt to imitate the sound of something large and heavy.

12. Tantrum

That outburst of anger called a tantrum first shows up in print in 1714. No one knows where it came from, and the usual authorities don’t seem to even have made any guesses about it.

13. Toad

Toad goes all the way back to Old English, but it has no known cognates in any of the related languages.

14. Curse

Some have proposed that the old word curse might have some connection with cross, but that connection hasn’t been established. It has no known relatives in Germanic, Latin, or Celtic languages.

15. Kick

At first etymologists thought kick might come from Welsh cicio, but it turned out cicio came from English kick. The idea that it comes from an Old Norse word for “bend backwards, sink at the knees” is another possibility, but it hasn’t been generally accepted.

This list first appeared in 2015 and was republished in 2019.