/,ʌndə'kʌvə(r); ,ʌndɚ`kʌvɚ/
adj [esp attrib尤作定语]
1 doing things secretly or done secretly; surreptitious 暗中进行的; 秘密做出的; 私下的
*,undercover`payments, eg bribes 暗中付的款（如贿赂）.
2 engaged in spying on people while appearing to work normallyamong them 做密探工作的
*,undercover `agents, activities ,organizations 密探、秘密活动、进行秘密活动的组织
* detectives working undercover 掩人耳目行事的侦探.

adj [only before noun]
undercover work is done secretly by the police in order to catch criminals or find out information
　an undercover investigation
undercover policeman/cop/agent etc
　undercover detectives
>undercoveradv
　a cop who goes undercover to catch drug dealers
　He worked undercover in Germany and Northern Ireland.