Fromcompletion +‎-ist.

completionist (comparativemorecompletionist,superlativemostcompletionist)

1. Engaging incompletionism.
   • 2016, Daniel Polansky, “A Sunday Sojurn” (chapter 19), inA City Dreaming‎^[1],→ISBN:

     M did not have thiscompletionist fetish regarding other matters—he would happily leave a meal uneaten and a book half read—but in matters of travel it was something of a matter of pride.

   • 2020, Michael Hinds, Jonathan Silverman, “The Networker”, inJohnny Cash International: How and Why Fans Love the Man in Black‎^[2],→ISBN, page171:

     Visiting the site was part of acompletionist project engaged by many Johnny Cash fans, who wanted to see all the places associated with him, but for some, it was enough to glimpse it without leaving the car.

   • 2023, Amanda Lewis, “Yew Complete Me” (chapter 8), inTracking Giants: Big Trees, Tiny Triumphs, and Misadventures in the Forest‎^[3],→ISBN:

     When I asked him about what drives ourcompletionist mindset, he said, "I think, as humans, we're obsessed with categorization and patterns. We see them everywhere, and we get a lot of pleasure from 'completing' things, whether it's a set of to-dos for the day or a larger project.[…]"

completionist (pluralcompletionists)

1. A person who practicescompletionism.
   • 2009 September 24, Seth Schiesel, “Visiting New Mombasa? It’s One Dangerous Burg”, inNew York Times‎^[4]:

     If you are a Halocompletionist and need to experience every moment of the Halo story, you have no choice.

   • 2010, Tom Waters,Slapstick & Superego: essays, rants & scathing social commentary‎^[5],→ISBN, page202:

     I rarely listen to any of them but I'm acompletionist and meticulous fanatic (for better or worse), and wouldn't want to miss any component from his recording career.

   • 2017, Jason Barr, “Collecting kaiju How Nostalgia Influences Toy Collecting”, in Camille D.G. Mustacio, Jason Barr, editors,Giant Creatures in Our World: Essays on Kaiju and American Popular Culture‎^[6],→ISBN, page199:

     To turn the discussion back toward kaiju toys, I argue that, unless I am acompletionist with significant cash flow, the toys I seek out will be those from which I will earn the most personal enjoyment.

   • 2019 October 31, Garrick Beckett, “Beckett: How BioWare Approaches Religion & Sexuality”, inThe Lutheran Column‎^[7], archived fromthe original on17 September 2020, Blog‎^[8]:

     I’ll be honest here: I’ve gone the romantic route in every game only because I wanted the achievement to add to my Xbox Gamerscore. I’m a semi-completionist when it comes to achievements, but once I got the achievement, I haven’t gone the romantic route again for the sake of my conscience.[…]
     To summarise this topic, if BioWare’s approach to premarital sex really bothers you, don’t go the romantic route. However, if you’re acompletionist like I am and want that achievement, by all means, get that achievement and don’t go the romantic route again.

• completionism