Da Dictionary.com Unabridged (v 1.1):
bookworm noun 1. A person devoted to reading or studying. 2. Any of various insects that feed on books, esp. a booklouse.
[Origin: 1590-1600; book + worm].
WordNet aggiunge un altro significato al primo riportato da Dictionary.com: a person who pays more attention to formal rules and book learning than they merit (synonim: pedant).
Non per niente, un ulteriore sotto-significato riportato dal Webster’s Revised Unabridged Dictionary è: a reader without appreciation.