a detective who wears civilian clothes on duty
They are usually picked up by plainclothesmen in four-wheel drives sometimes there are policemen with them, sometimes not.
NEWYORKER: Days of Rage
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。