Important Query About Important People

There are numerous halachos in Shas [in the present daf-yomi masechta Moed Kotton] which apply to an אדם חשוב. In tonight's shiur, the Rebbe Shlita discussed at length the following question: What classifies someone as an אדם חשוב? If anyone has seen this discussed or has any orignal ideas I would love to hear....

It is strange that almost nobody adresses this question. It is also strange that the poskim define quite clearly what an אשה חשובה is [nafka minah that she does הסבה]. Why does אדם חשוב remain vague while אשה חשובה is clearly defined?