Main Entry: di·a·bol·i·cal

Pronunciation: \ˌdī-ə-ˈbä-li-kəl\

Variant(s): or di·a·bol·ic \-ˈbä-lik\

Function: adjective

Etymology: Middle English deabolik, from Middle French diabolique, from Late Latin diabolicus, from diabolus

Date: 14th century

: of, relating to, or characteristic of the devil : devilish <a diabolical plot>

— di·a·bol·i·cal·ly \-li-k(ə-)lē\ adverb

— di·a·bol·i·cal·ness \-li-kəl-nəs\ noun