Glowy-Is it a new word? [closed]

Yes, it's a word. Depending on your definition of "new," it could be centuries old or (in current usage) at least 35 years old.

Glowy is a formation made from a noun (glow) and a generative suffix (-y, described in Merriam-Webster as "characterized by" and other meanings). The suffix can be used to create nonce words (words created for singular occasions) that, irrespective of their aesthetic qualities, would be understood by speakers. Here, I'll play around with some nouns I've just used to invent words:

That word ending is suffixy.

A gerund feels nouny.

This is getting nonce-wordy.

Because someone can take an existing word, add a generative prefix, and trust that many speakers will recognize it, glowy (characterized by glow) is a word.

Is it an acceptable word? It certainly appears in print. It's a word that has been used periodically since at least the 1980s, as I found in COHA. This is from novelist Alice Walker in The Color Purple from 1982:

They black and smooth and kind of glowy from the lamplight.

Then here's another from Malcolm Gladwell in Blink (2005):

They haven't been married that long. They're still in the glowy phase.

This usage has begun to appear in dictionaries. Here's Lexico:

(informal) Giving off a steady light.

‘soft, glowy bulbs’

Note that this definition is pretty general. It doesn't describe the figurative usage Gladwell seems to employ - does a new marriage literally give off a steady light? No - this must come from figurative senses of glow, like ": warmth of feeling or emotion" (Merriam-Webster). Glowy retains the figurative uses of its root noun as well as the literal one.

Also note that the word does feel informal. I might avoid glowy in an academic essay, but glowy would be in my word hoard for creative writing and writing for a general audience.

Finally, it's a word that has existed before. The Oxford English Dictionary marks an obsolete use with a very similar meaning:

Glowing; bright.

1670 S. Wilson Lassels's Voy. Italy (new ed.) i. 154 This fire..appeared to mee..to be..of the same glowy colour.

Early English Books Online turns up 9 results, showing it's not merely a nonce usage. So it is an old word that has recently been reinvented.