相关单词近义词 secrecy 秘密, stealth 秘密行动, concealment 隐匿, hiddenness 隐藏临近词covert, covert communication, Covert Viewing System, covert twill coatings, covert commando force, covert timing channel, covert mandatory plan, covert desensitization, covertly sun-shading, covert modeling therapy, covert face recognition 返回 covertness