What does the term "Bad Moon" actually mean?
        It seems to be a reasonably common phrase. Several "famous"
        people and groups have taken it as their name, various forms of 
        fiction have used the term openly. But it's not in the online
        dictionaries i have researched, and there is no easily accessed
        definition through the search engines i've checked.

        So, i looked to the internet blog, and reviewed, literally,
        HUNDREDS of websites. These are my findings:

    www.spiritone.com/~filipas/Masquerade/Reviews/templrs.html makes reference to the waning
    moonphase as a "bad period" and directly calls the last quarter of the moon a "bad moon".
    That would seem to be the answer for it, then, eh?

    http://www.thaicov.org/resources/contextualize/voices_7.html mentions, in footnote 6,
    that the waning moon is considered bad luck.

   Additionally,

    --- the color black generally means "bad" 
    --- when the moon is dark, you can't *see*, unless your vision is exceptional, in which
        case YOU are considered bad


    I have always favored the idea that a bad moon was the second dark moon in a calendar
    month. The truly scant information i have located makes me want to prefer the idea that
    a bad moon could be the waning moon prior to AND the dark moon of a second dark moon
    in any given calendar month.