diabolic

Etymology

First attested between 1350 and 1400 from Middle English diabolik, from Middle French diabolique, from Late Latin diabolicus, from Ancient Greek διαβολικός (diabolikós, “devilish”), from διάβολος (diábolos, “devil”).

adj

1. Showing wickedness typical of a devil.
   "The Sovereign Council of Wisdom," or the Order of Palladium, founded in Paris, was a diabolic order claiming masonic origin. 1936, Rollo Ahmed, The Black Art, London: Long, page 259
   diabolic magic square
   a cunning and diabolic plot
2. Extremely evil or cruel.
   fires lit up a diabolic scene