The Collaborative International Dictionary of English v.0.48:

Bookseller \Book"sell`er\, n.
   One who sells books.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bookseller
    n 1: the proprietor of a bookstore

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "bookseller":
   baker, bibliognost, bibliographer, biblioklept, bibliolater,
   bibliomane, bibliomaniac, bibliopegist, bibliophage, bibliophile,
   bibliopole, bibliopolist, bibliotaph, bibliothec, bibliothecaire,
   bibliothecary, book agent, book collector, book printer,
   book publisher, book salesman, book-stealer, bookbinder,
   bookdealer, booklover, bookmaker, bookman, bookworm, butcher,
   cataloger, chandler, chief librarian, clothing merchant,
   college editor, confectioner, copy editor, curator,
   dictionary editor, draper, drysalter, editor, editor-in-chief,
   executive editor, fishmonger, fishwife, florist, footwear merchant,
   fruiterer, furnisher, furrier, greengrocer, grocer, groceryman,
   haberdasher, hardwareman, ironmonger, jeweler, juvenile editor,
   librarian, library director, liquor merchant, managing editor,
   newsdealer, perfumer, permissions editor, philobiblist, poulterer,
   printer, production editor, publisher, reference editor,
   reference librarian, saddler, stationer, textbook editor,
   tobacconist, trade editor, vintner, wine merchant