Fab word. It's often acceptable @severine to use a noun as an adjective. Your example, ending in 'ing' and being largely unknown, would pull me up for a stop and think. If you post your intended sentence it may be better to get a grasp of whether it'll work or not.
If you're a writer, you're allowed to be creative . Just make sure your noun is not a repetition of your adjective. "the gloaming twilight" won't work since it will mean the twilighting twilight. Apart from that, no prob.
I think the combination of archaic plus non-standard usage might be a bit much... I know the word because of that campfire song, but I feel like I'm only really comfortable with it in that construction. Not just "gloaming" on its own, but the full-on "in the gloaming" phrase. I'm really not sure how it would feel if I saw it without the extra words, let alone as an adjective.
Why use a word almost no one will recognize? Especially when dusk, twilight, and nightfall are all prettier sounding. I could see it if gloam was one of those words that sounds like what it means, but it isn't. It's not that I don't occasionally use archaic words, and at times in grammatically questionable ways, but I always make sure the word in question is obvious in it's meaning. Below, is a passage wherein I use winnowed, incorrectly. I chose the word for good reason. The magpie is ridding Adeline of the things she no longer needs, removing the chaff from her life, so to speak. Because winnowed brings to mind a pleasant sound and perhaps a feeling of affection and tenderness, I went ahead and used it. You'll also notice that I used crooked instead of cocked its head... the magpie is an accomplished thief, a crook! Winnow: blow a current of air through (grain) in order to remove the chaff. Mabel turned to Adeline, saving a snide remark for the fussy girl, but held her tongue. Adeline had gone quiet and was staring blankly into the fire with her hands tucked between her knees. Mabel took the rabbit bone and tossed it at Rosemarie, then motioned for her to take notice of the other girl’s sullen mood. Rosemarie shooed her demoralized cat from her lap, and with the magpie still perched on her finger, stepped around the fire and knelt beside Adeline. “I don’t know if it’s providence or you simply have an uncanny knack for coincidences, but somehow Josephine found her way to you and now there’s no getting out of it. So stop sulking and put your finger out.” Adeline refused to turn from the fire, but poked an angry finger out as if daring the fickle bird to come to her. Without having to be prodded in the least, Josephine hopped from Rosemarie’s finger onto Adeline’s. Begrudgingly, Adeline pulled her stare from the flames and met Josephine’s ink-drop eyes. The magpie crooked its head and winnowed at her.
This is like asking why use turmeric when we already got salt and pepper. Because funky words are the spice in a book. Because it's boring to read the same stuff over and over and it's much more fun to read something described differently.
She only continued staring, her brown eyes meet those gloaming green. I'm describing a water monster, and I chose gloaming to contrast with the previous paragraph where I described said monster's eyes as gloomy. Perhaps you're onto something there about the combination, thank you. I've never heard of the campfire song at all. Thank you everyone for your input , it's much appreciated.
I tend to think any new construction is masterful - until - until - well, the world doesn't delete need to know ... Use 'gloaming' to parody the source - aligned with a sense of domestic misery/miserable/fat/ a gloomy household maybe in heather at twilight with the English lecturer?