What term describes a situation where conventional rules of grammar are unable to produce an idiomatically formed word for a particular context?

I recently saw the question Is the spelling beautifuly correct? at ELL.

Before I even looked at it, I had thought of a joking response:

✘ No, it's ugly incorrect.

But I quickly stopped myself, realizing that wasn't right. I then very briefly thought of the following variations:

✘ No, it's uglily incorrect.
✘ No, it's uglilly incorrect.
✘ No, it's ugily incorrect.
✘ No, it's ugilly incorrect.

Of course, none of those is right either.

Although I'll note that each of those suggestions follows a generally correct approach to changing such an adjective into an adverb.

  • Happyhappily.
  • Jollyjollily.

I'll add that ugly is actually an adverb:

[Merriam-Webster]
: in an ugly manner
// was acting ugly

However, the sentence construction in which its adverbial form is grammatically used doesn't match the construction of the sentence I'm looking at here.

I'll also add—thanks to an answer provided in response to the original version of my question before this edit——that Merriam-Webster does actually show this:

Other Words from ugly
Adjective
uglily \ ˈə-​glə-​lē \ adverb

I was surprised to have missed this, and to find that it exists in the first place. Still, I'd say that's so unusual that, even if it were expected by some audiences, most would mark as a mistake on the grounds of it being unidiomatic.


The sentence could be rephrased or the base word changed:

✔ It's beautifully correct.

✔ No, it's grotesquely incorrect.
✔ No, it's an ugly incorrect spelling.

But that means either dispensing with ugly altogether, or altering the sentence to accommodate ugly in a way that beautifully does not require.


So, to restate:

✔ It's beautifully correct.
✘ It's (ugly) incorrect.

Is there a word that expresses the fact that ugly cannot be turned into an acceptable adverbial form in the same way that beautiful can be turned into beautifully?

In short, what word or linguistic descriptive term would be used to describe this so-called intransigent aspect of ugly?

If used in a sentence:

In this context, the word ugly is _____.

The adjective (or phrase) should mean that the word cannot be reformed in a grammatically and idiomatically acceptable way.

I'm specifically focused on the word ugly and its inability to be turned into something acceptable, but, as with the title of this question, will be content with a word or phrase that describes this phenomenon in general.


https://groups.google.com/forum/#!topic/alt.usage.english/qoIklspnMN8

What's the adverb that goes along with the adjective "ugly"?

Believe it or not, it's 'uglily'. Ain't that ugly?

There's a verb 'uglify', meaning 'make ugly', and from there we derive the noun 'uglification', which Prince Charles recently hit the headlines for using. The Times described it as an 'excrescense'; I've waited until now for a chance to mention that little irony.

https://www.merriam-webster.com/dictionary/ugly

Other Words from ugly Adjective

uglily \ ˈə-​glə-​lē \ adverb