Possible Clues:

• English physician who devised a classified list of synonyms
• Thesaurus guy
• Name on many thesaurus books
• Physician/synonymist
• Thesaurus publisher
• You might take his word for it
• Collector of words I acknowledge has new base
• Subject of Joshua Kendall's "The Man Who Made Lists"
• Big name in synonyms
• His 'Thesaurus of English Words and Phrases' was published in 1852