这个短语的字面解释是“好镜片、差镜架”，这是什么意思呢？请看对话：

    A: My kid caught a cold last week and has not fully recovered. Do you know any pediatrician that is nice and experienced?

    B: Sure, I’d like to recommend Dr. Bruce. He is a spaz, but he’s one of the best doctors I know. You wouldn’t know it by looking at him, you know, good lenses, bad frames.

    Note: It’s easy to understand the expression if you think of a pair of spectacles, with good lenses and bad frames. Obviously, they are of good quality but the appearance is not impressive. According to urbandictionary.com, the term describes someone who gives a bad first impression but is actually a good person.This could be someone who doesn’t appear to be competent, yet is extremely capable at what he/she does.