yapper

noun3

1. •
   One who yaps.

   • I have to admit I would have a lot more tolerance for cell phone yappers on my one-hour train ride to and from work if they were actually learning — instead of yelling […] — 2007
2. •
   (informal) Ellipsis of yapper dog

   • If you’ve got a yapper dog, take him somewhere else. — 2011
3. •
   (slang) A person's mouth, especially one that gossips or talks too much.

   • Shut your yapper or I'll shut it for you!