Word Sponge
A person who is devoted, and addicted, to reading.
Jimi Herndon is a serious "Word Sponge"! He soaked up 72 books in 52 weeks! Amazing!
Word Sponge
Someone who, when participating in a conversation, chooses to say little no words, generally because they have nothing interesting to contribute.
That guy was a real word sponge, he didn't say a single thing.