A cacodemon (or cacodaemon) is an evil spirit or (in the modern sense of the word) a demon. The opposite of a cacodemon is an agathodaemon or eudaemon, a good spirit or angel. The word cacodemon comes through Latin from the Ancient Greek κακοδαίμων kakodaimōn, meaning an `evil spirit,` whereas daimon would be a neutral spirit in Greek..... Found on http://en.wikipedia.org/wiki/Cacodemon
Cac`o·de'mon noun [ Greek ..............................; kako`s bad + .................. demon: confer French cacodémon .] 1. An evil spirit; a devil or demon. Shak. 2. (Medicine) The nightmare. Dunaglison. Found on http://www.encyclo.co.uk/webster/C/3