Definitions
1.NounA collector who strives to obtain a complete collection of some type of thing, especially a fan who aims to own or consume the complete output of a particular author, publisher, musician or band.
2.NounA person who champions any philosophy which focuses on the completeness of something."A completist philosopher holds that a definite complete body of knowledge exists to be discovered."
3.AdjectiveWhich attempts to collect something completely.
4.AdjectiveAlternative spelling of completest.