One of the innovations of Newspeak, the version of English used by the totalitarian government in Orwell’s dystopic novel Nineteen Eighty-Four, was the elimination of antonyms. A writer at the Oxford Dictionaries site explains:
By choosing which words the populace can use, The Party can choose to shift thought in a more positive or negative direction to suit their needs; ungood, for example, makes the populace feel less negative than bad would…
In 2015, some of the populace seem to be choosing to add un- to adjectives like good and rich rather than look for conventional antonyms:
The Rich Are Less Ethical Than the Unrich
[A Resort] Like Palm Springs, only for unrich people
The government is clearly pandering to the masses, i.e. the unrich people.
Few fanfic writers actually write good stories. Some are unrealistic, unplanned, ungood stories.
I was all set to move to Erdington until last night [when] I found some ungood stories about the area I will be living in.
In the end, the good outweighed the ungood and I’m happy I chose this place.
I’ll be traveling light when it comes time for me to cross, when I cross…
This unwide road… (song lyrics) .Abercrombie & Fitch chief executive Mike Jeffries [issued] a half-baked apology for his incendiary comments on why the unthin, the unyoung and the unbeautiful don’t belong in A&F clothes.
As a stylistic device, words like unthin and unbeautiful can be used to humorous effect. Adding un- to words in an effort to obscure meaning or avoid thought, on the other hand, is not an option for writers who wish to be taken seriously.
Unclear, and uneconomical to boot.
Ungood: six letters, two syllables, might be verbally confusing.
Bad: three letters, one syllable, verbally unambiguous.
Let’s not start on double-plus-ungood.
Ungood might work well in a poem, if you don’t care to be taken too seriously.
I understand the construction and concept, but don’t use these words in my own vocabulary. I might in the future, if I remember to do so and if the situation lends itself. Sadly (for me) I am so behind the times sometimes, that I had to go and read up on the Abercrombie & Fitch story, of which I was unaware. I mean, not aware. I mean, ignorant. Whatever!