According to someone on Namenerds, it could mean of the devil. Her reasoning: As far as the etymology goes... dysdaimon, the Greek word that it comes from, contains two elements - dys and daimon. Daimon is also the word that "demon" was derived from. In Greek, though, and someone can correct me if I have this wrong, daimon was used for all theistic beings that weren't gods (ie spirits). Dys simply meant bad, so a literal translation then might have been "bad spirit" - so "of the devil" might not be far off.