On the sporting fields of New Zealand cities like Auckland and Wellington in the late 1990s and early 2000s, the slightly-too-cool kids were jokingly described with one word: “skux.” To be skux was to be popular, good-looking and also possibly a little bit conceited — ultimately it was a compliment.

The word, which has somewhat fallen out of use in the intervening years, popped back up on social media this week in tributes following the death of the actor Sam Neill. While it may seem a random jumble of letters, in New Zealand, it is a term of endearment and affection.

As with the origin stories of most slang terms, tracing the roots of “skux” is difficult, but the most common theory is that it emerged, as most good things do, by chance, in the New Zealand capital, Wellington.

The New Zealand writer Madeleine Chapman traced the word’s etymology for The Spinoff website. She found that “skux” was predominantly used by men in New Zealand’s Pacific communities in the late 1990s and early 2000s to refer to other men they thought were cool but vain.

“It was a little bit sort of mocking a person for putting that much effort into their appearance, but at the same time, you couldn’t be a skux unless you also looked good,” Ms. Chapman said in an interview.

Ms. Chapman wrote that the term most likely came into use around 1997, when two Samoan teenage boys living in Wellington saw an Italian ad in which a good-looking man used the term “Scacco matto” (checkmate). The boys wondered if there was a Samoan word to describe a handsome man who would use a line similar to the Italian actor. They eventually settled on “Sikaki” — which, coincidentally, means “study,” Ms. Chapman wrote.

Over time, the word evolved, and “skux” entered New Zealanders’ lexicon. (Different spellings are permissible. It is sometimes written as “skuxx.”)

The Samoan teenagers who coined the phrase went on to play international rugby. Ms. Chapman wrote that one of them, the All Blacks player Ma’a Nonu, was given the moniker Skux.

The word’s definition has since evolved and now describes someone who knows “they’re cool, but is even cooler than that” and can be used for people of all ages, genders and backgrounds, Ms. Chapman said.

Slang terms are often associated with a particular demographic, and so their use signals belonging to that group, said Arianna Berardi-Wiltshire, a linguistics lecturer at Massey University in New Zealand. But it is common for their definitions to become more generalized as they spread through the population, she added.

The Canadian rapper Drake used the term during his concert in Auckland in 2015, and “skux” gained more international attention when it featured in the 2016 film “Hunt for the Wilder People,” written and directed by Taika Waititi, a New Zealand native.

In one scene, as the police close in on the gruff Uncle Hec (Mr. Neill) and the rebel Ricky (Julian Dennison), the younger New Zealander yells, “I didn’t choose the skux life, the skux life chose me,” before crashing his car into a corrugated iron fence and yelling “freedom.” The line made its way onto shirts and stickers.

After the news of Mr. Neill’s death, Mr. Dennison said in a post on social media that he would hold onto the lifetime of memories from making the film and thanked his co-star for being the “skuxxest.” The term was used in many other tributes to Mr. Neill. Skux also made its way into Mr. Neill’s obituary on the Australian satirical website The Betoota Advocate, which wrote that he had led “the skux life.”

Mark Broatch, the author of “100 Words That Make Us Kiwi,” said a lot of New Zealand English is influenced by Australia, Britain, the United States, and Maori — the Indigenous language.

“I doubt any other form of English uses so much of the language of its first people. There has also been some Pasifika borrowing, given our place and role in the Pacific,” he said, referring to people from the Pacific islands who now call New Zealand home.

Mr. Broatch said one peculiarity of New Zealand slang was the addition of “y” or “ie” to words — seen in common local words: bikkie (biscuit), littlies (young children), mozzie (mosquito) and wettie (wet suit). A babycino — or kid-friendly cafe drink — in New Zealand is known as a “fluffy.”

Although skux has faded from New Zealand’s lexicon, Mr. Neill’s death this week saw a resurgence of the term. And Ms. Chapman said no one would dispute its application to Mr. Neill.

“The original skuxes combined stereotypical masculine traits (rugby, power) with a gentler presentation (eye makeup, hair straightening, simply caring at all),” she said.

“Neill was a classic Kiwi bloke but with a beautifully gentle way of presenting himself,” she said, “especially in his love of land and animals. Very skux.”