what exactly does navillera mean?

Apparently it's from Cho Chi-hun's poem "The Nun’s Dance". And is created by the author to describe the fluttering of a butterfly, yeah. Sort of like an onomatopoeia I guess. It's written as "나빌레라". And 나비 is butterfly in korean.

But there's also the book "Le Papillon des étoiles" from 2006, which seemingly was also a big inspiration for at least the song Navillera (2016). That's probably what the other commentor is referring to. But I'm not sure it's directly connected to the word itself.

I am Korean so I know NAVILLERAmeaning. Navillera is old Korean. Usually Korean aren't use it. Navillera means beautiful with some soft. In the Joseon Dynasrt, they use the word when they watching traditional dance. 춤을 나빌레라하게 춘다. Like this. 나빌레라 is like a butterfly. Butterfly is 나비 and 레라is hearing like meaning beauty. So 나빌레라 meaning beauty like a butterfly. I am not an expert if I wrong. And I am not good at English so I must wrong grammer.

I translated this explanation I found. Sorry in advance for any mistakes:

Navillera is a word that is part of the first line of Cho Ji-hoon's Korean poem "Seungmoo" (Dance the Monk) (1920-1968). The word was invented by the poet, implying that something is stirred (in the case of the poem, the monk's costume). Although the author never expressed its true meaning, some critics argued that it indicated that an object came to life, in something similar to a butterfly and because the word sounds good, it was popularly welcomed to refer to small things, which have the grace of these insects.

'Navi' as '나비' means butterfly. The etymology of 'Navi'(나비) comes from 'Naab'(납) or 'Nalb'(낣) which is an archaic word and it means flat-shaped, a condition that is easy to be flying in the wind. 'Nak-yup'(낙엽) means falling leaves, 'Na-baang'(나방) means a moth, 'Napulgurida'(나풀거리다) means a flat flag things flapping in the wind.

Naab(납) or Nalb(낣) + -y (-이) indicates someone. So, Naa-vy (나비) is someone flapping in the air hard to catch. *The ancient Korean people called monkeys Jannabi(잔나비). Jan(잔) means someone who is mischievously playful.

'-lera' (-레라) of Navillera is an abbreviation of '-il le ra' (-일레라).

'-il le ra!' (-일레라!) is an old saying with exclamations like 'something like that!'. So, 'Navi il le ra' means 'it looks like a butterfly' or 'it's a butterfly'. As many people said, a poet 'Cho chi-hoon' wrote that sentence in his poem. And he is known to use old archaic words very well.

The title is 'A Buddhist's (Nun's) dance' and the full sentence is,

'얇은 사 하이얀 고깔은 고이 접어서 나빌레라'

a thin gauze, a white peaked hat, fold it sincerely, it looks like a butterfly.

Here is a link for that image.>https://img1.daumcdn.net/thumb/R720x0.q80/?scode=mtistory2&fname=http%3A%2F%2Fcfile28.uf.tistory.com%2Fimage%2F9933854F5AB0C74A2CB993

As the photo tells, the dancer throws a long piece of gauze on the arm into the air. And it looks like a butterfly, the poet says. It's like a ritual to cast out deep sorrow.
'A Buddhist's (Nun's) dance' is a poem that means preparing for dance while enduring deep sorrow and grief, and eventually soar as like there's no gravity.

So, Navillera doesn't mean just looks like a butterfly but also means enduring pain and sadness.

Kinda late but i want to share this information (my bf did the researches, i just translate it)

We don't know what is the language of the word "navillera", but some say it is an old korean word. Navillera is kind of a combination of “nabi/navi” and “lera/rera”. “Nabi/navi" (나비) in korean means "butterfly" and "lera/rera” (레라) means “like, alike” (not used in normal conversation). In conclusion, Navillera can be known as "like a butterfly"

The word "navillera" once appeared in a poem named "Seungmoo 승무" (The Dance of Buddhist Nun), written by Cho Ji-hoon 조지훈 (1920-1968) when he was 19. The poem “Seungmoo” is about the dance of the clergymen in Long-sleeved Buddhist monk costume in "Seungmuje 승무제" (Buddhist ritual dance festival) - a traditional Buddhism dance festival of Korea (https://bit.ly/3bUlYjD), the dance embodies a feeling of sincere penance for past wrongdoings and aspire to seek eternal truth.

That line of the poem: “얇은 사 하이얀 고깔 은 고이 접어서 나빌레라” (Yalbeun Sa Haiyan Gokkaleun Goi Juboso Navillera) (A sheer white silk'n hood folded fairly, I wonder if it were a flying butterfly). According to the poem, "navillera" means "flying intermittently”, describing the nun as a little thingy flying in the traditional dance.

Besides, sone people assume that "navillera" is related to a novel named Le Papillon Des Étoiles (The Butterfly of the Stars) of a French writer, Bernard Werber which was published in 2006.

This is so interesting. There is a little butterfly on the series banner, right after the title, “Navillera.” The butterfly suits the theme of the story very well. It’s graceful (which seems to be emerging as the general definition of navillera) and it also symbolizes rebirth (caterpillar to butterfly). The characters, through dance, are striving for graceful movement, and they are also struggling to be “reborn” in order to be and do what they love. Those are just my ideas. I’m pretty certain the word will be explained in a future episode because the person who knows the real answer is the writer!

if im not mistaken, it comes from a French poem, not a Korean poem. The book was popular in Korea though

Always thought it was a Spanish word

Regarding the spelling:

나빌레라. The consonant blocks are 나 빌 레 라

나: Na

비 (from the block 빌): Normally romanized as 'bi' but ㅂ is often used to represent 'v' if there's anㅣ('i' sound) somewhere in the consonant block.

레 and 라: ㄹ is the letter romanized as either R or L. It sounds different based on where it falls within a word. It's related to where your tongue is positioned within your mouth after pronouncing the previous sound. The first block sounds a more like an 'l', and the second one sounds more like an 'r'.