Not able to be mailed; specifically (US) not admissible to mail services for dispatch or delivery.
Mid 19th century; earliest use found in New York Herald. From un- + mailable.
英语词典包含464360条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。