Tattlesome

The apparition frightened her, and she had dropped the plate. Newt thought of Priscilla as most boys his age thought of older sisters—meddlesome, tattlesome, scary, curious and unsociable.

Now, before my reader believes that Arwen was being tattlesome, you must understand that very often things - most times bones - were broken when the twins fought, and Arwen was under strict orders to report any such offenses while they were still young.