Definitions:

1. Overly talkative. ADJECTIVE
   • Why is everyone over there so blabby with this guy?
2. Unwisely talking too much. ADJECTIVE
   • In English, blabby talkers have been called leaky since the late 17th century.

Synonyms:

• bigmouthed
• blabbermouthed
• chattery
• gabby
• taletelling
• talky
• wordy