是广东话的“面无表情”的意思。http://bbs.cantonese.asia/viewthread.php?tid=16346 这里有视频可以看看。

这是广东话方言，类似的有湖南话的“瓜头瓜脸”，在中国某些地方的文化认为“木”“瓜”什么的词代表“傻”“笨”“不会动”"no alive". anyway, no any expression in someone's face.like "amimia" i come from china.add my skype id:"shelvinglee" to learn mandarin.

Maybe，"木头木面"是指一个人傻傻的（silly）发呆，或是遭遇到什么不好的，突然的事情而不知道该怎么办的时候的一种呆板的面部表情。你是否已经了解呢？呵。

应该是方言吧，像普通话的‘呆头呆脑’形容一个人愚笨

As a Chinese, I have no idea what that is, never heard of it. IF, there exists such expression, you don't have to know it. If it appears again somewhere else, you can easily tell the meaning from the context, but I think those chances are very very slim.