Leaving the definition of "clean" ambiguous does give you some useful information, though, because the context implied by the answer shows you something about t

Leaving the definition of "clean" ambiguous does give you some useful information, though, because the context implied by the answer shows you something about the interviewee's priorities. Of course their code is "clean" according to whatever metric is important to them - but what's their metric? What are they focusing on as they work?