I've been looking at the adjectives "curious" and "furious", and have been wondering why their noun counterparts are so different.

According to etymonline, the origins of these words are:

"furious" comes from French "furieux" from Old French "furios" from Latin "furiosus" ("full of rage, mad"; related to "furia" ("rage, passion").

"curious" comes from French "curieux" from Old French "curios" from Latin "curiosus" ("careful, diligent"); related to "cura" ("care").

Now, why is it that -- despite these two words having a similar structure at each point in their history -- their English nouns are so different, when their adjectives are so similar?

Why do we describe people as "curious" and "furious" but call these attributes "curiosity" and "fury"? Why not "cury" and "fury"? Why not "curiosity" and "furiosity"?

At what point in the evolution of these nouns did they start to diverge, and why?

  • 3
    You should probably also look at the etymology of "fury," it may give more relevant information. "Fury" seems to be from Latin "furia," with a similar meaning; but Latin "curia" never seems to have meant "curiosity."
    – herisson
    Mar 17, 2017 at 19:04
  • @sumelic I don't see how the fact that it originally meant something quite different is relevant. Why not "furiosity", then?
    – alexqwx
    Mar 17, 2017 at 19:21
  • You could also add "spurious" to the mix.
    – Ricky
    Mar 17, 2017 at 19:46
  • 4
    I think @sumelic mentioned the etymology of fury because, if you're trying to compare "fury" and "curiosity", it makes sense to look at their etymologies. As opposed to the (less helpful) etymologies of "furious" and "curious". The adjectives and nouns have taken different paths, though they share similar roots. Mar 17, 2017 at 19:57
  • 2
    In other words, the etymology of the nouns and the adjectives branched way before they even entered English. They diverged in Latin. So despite the fact that they look similar in English, and share similar roots, strictly speaking in English "fury" and "furious" come from different things. Mar 17, 2017 at 20:03

1 Answer 1


Many adjectives end with the letters ...ious. From the list below (taken from Spellzone) I can only see three which support nouns like fury - melodious (melody), harmonious (harmony), and victorious (victory). The rest have nouns that are connected in a variety of ways, some with no noun connection at all.

amphibious (amphibiousness?), curious (curiosity), delirious (delirium), devious (deviousness), dubious (dubiety), furious (fury), harmonious (harmony), impervious (imperviousness), melodious (melody), notorious (notoriety), oblivious (oblivion), obvious (obviousness), precarious (precariousness), previous (none), rebellious (rebelliousness), serious (seriousness), studious (study - a verb), tedious (tedium), various (variety), victorious (victory, victoriousness)

As regards the two you mention, whilst their etymologies are both French, as @sumelic has pointed out, they were treated quite differently to one another in Latin. That is perhaps relevant. The OED says, in respect of each:

Etymology: < Old French curius ( Ch. de Rol., 11th cent.) = Provençal curios, Spanish curioso, Italian curioso < Latin cūriōsus used only subjectively ‘full of care or pains, careful, assiduous, inquisitive’; French has also the objective sense in 14th cent. (robes curieuses). A word which has been used from time to time with many shades of meaning; the only senses now really current are 5, 16, and (in some applications) 9.

Etymology: < Old French furieus (modern French furieux ), < Latin furiōsus , < furia fury n.

  • various :: vary.
    – Nij
    Mar 18, 2017 at 5:45
  • 2
    injury ... injurious // mercury ... mercurious // luxury ... luxurious // perjury ... perjurious // penury ... penurious // usury ... usurious follow the 'fury ... furious' pattern. Mar 18, 2017 at 8:34
  • @EdwinAshworth yes. Very good examples.
    – WS2
    Mar 20, 2017 at 8:21
  • @Nij Vary is a verb - variety the noun.
    – WS2
    Mar 20, 2017 at 8:22
  • I was wondering if ferocious/ferocity muddled things up wrt furious/fury. And of course, there are the Furies, which aren't the Furocities.
    – Phil Sweet
    Sep 3, 2018 at 1:39

Not the answer you're looking for? Browse other questions tagged or ask your own question.