1. a person who tries to collect or obtain every item in a particular series or category

Examples

• As a completist, she owned every album the band had ever released.
• The video game completist spent hours finding every hidden item.
• He’s such a completist that he reads every book by his favorite authors.
• The stamp completist was missing only one rare issue from 1952.
• Being a completist can be expensive when collecting vintage comics.
• The completist mentality drove her to visit every national park.