Emily Dickinson Lexicon

ROIST, or ROIST'ER, v.i. [Arm. reustla, to embroil. This word belongs to the root of rustle, brigade, Sax. brysan, to shake, to rush, W. rhysiaw, to rush, to straiten, to entangle, rhysu, id.]

To bluster; to swagger; to bully; to be bold, noisy, vaunting or turbulent. [Not in use.] – Shak. Swift.