英汉词典

1. 哑的;不能说话的
    Someone who is dumb is completely unable to speak.

    e.g. ...a young deaf and dumb man.
           年轻的聋哑男子

2. (在某种场合下因愤怒或惊讶而)说不出话的,哑口无言的
    If someone is dumb on a particular occasion, they cannot speak because they are angry, shocked, or surprised.

    e.g. We were all struck dumb for a minute.
           一时间我们惊讶得哑口无言。