bolt upright

== English == === Adjective === bolt upright (not comparable) Vertical, with the back held stiffly. ==== Translations ==== ==== References ==== “bolt upright”, in Cambridge English Dictionary, Cambridge, Cambridgeshire: Cambridge University Press, 1999–present. “bolt upright”, in Collins English Dictionary, 2011–present. “sit bolt upright”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present. “sit stand bolt upright” in Longman Dictionary of Contemporary English, Longman.