The Collaborative International Dictionary of English v.0.48:

Loquacious \Lo*qua"cious\, a. [L. loquax, -acis, talkative, fr.
   loqui to speak; cf. Gr. ? to rattle, shriek, shout.]
   1. Given to continual talking; talkative; garrulous.
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            Loquacious, brawling, ever in the wrong. --Dryden.
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   2. Speaking; expressive. [R.] --J. Philips.
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   3. Apt to blab and disclose secrets.
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   Syn: Garrulous; talkative. See Garrulous.
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WordNet (r) 3.0 (2006):

loquacious
    adj 1: full of trivial conversation; "kept from her housework by
           gabby neighbors" [syn: chatty, gabby, garrulous,
           loquacious, talkative, talky]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "loquacious":
   all jaw, candid, chatty, communicative, conversational, effusive,
   expansive, flip, fluent, frank, gabby, garrulous, gassy, glib,
   gossipy, gregarious, gushy, jabbering, long-winded, loose-tongued,
   multiloquent, multiloquious, newsy, overtalkative, prolix, smooth,
   sociable, talkative, talky, verbose, voluble, windy, wordy