Lexicographer

A lexicographer is a person devoted to the study of lexicography, especially an author of a dictionary.

Some famous lexicographers:

Samuel Johnson
Noah Webster
Isaac Kaufmann Funk
James Murray
Henry Bradley
William Craigie
Charles Talbut Onions
Henry Watson Fowler
A. S. Hornby

Johnson famously defined a lexicographer as "Lexicographer: A writer of dictionaries; a harmless drudge that busies himself in tracing the original, and detailing the signification of words".