diabolical

adjective

di·​a·​bol·​i·​cal ˌdī-ə-ˈbä-li-kəl 

variants or diabolic

ˌdī-ə-ˈbä-lik 

: of, relating to, or characteristic of the devil : devilish

a diabolical plot

diabolically

ˌdī-ə-ˈbä-li-k(ə-)lē 

adverb

diabolicalness

ˌdī-ə-ˈbä-li-kəl-nəs 

noun

Did you know?

Like the word devil, "diabolical" traces back to Latin diabolus, which itself descends from Greek diabolos, a word that literally means "slanderer." In English, "diabolical" has many nuances of meaning. It can describe the devil himself (as in "my diabolical visitor") or anything related to or characteristic of him in appearance, behavior, or thought; examples include "diabolical lore," "a diabolical grin," and "a diabolical plot." In British slang, "diabolical" can also mean "disgraceful" or "bad," as in "the food was diabolical."

Synonyms

• demonic
• demonical
• sinister
• evil
• malicious

Examples of diabolical in a Sentence

the police quickly mobilized to track down the diabolical criminals before they struck again

Recent Examples on the Web

The event includes a beer, then beer pong, a second beer, then cornhole, a third beer, then flip cup, a keg race, then the diabolical Run, Forrest, Run race around the block — two times! —Ben Crandell, Sun Sentinel, 3 July 2025

Theologian, pastor and writer, Bonhoeffer had a role in a scheme to remove Hitler from power because of Hitler’s diabolical persecution of Jews and others. —Walt Shelton, Austin American Statesman, 2 July 2025

The Oscar-winning actor and filmmaker will reportedly portray the husband of Streep’s diabolical fashion magazine maven Miranda Priestly. —Karu F. Daniels, New York Daily News, 30 June 2025

These diabolical onslaughts are further weaponized by the reckless defunding of scientific and medical research and the undermining of public libraries (including the Library of Congress), museums, and other cultural institutions. —Donna Seaman june 18, Literary Hub, 18 June 2025

Word History

Etymology

diabolical from diabolic + -ical; diabolic going back to Middle English deabolik, borrowed from Middle French & Late Latin; Middle French dyabolique, borrowed from Late Latin diabolicus, borrowed from Late Greek diabolikós, going back to Greek, "slanderous," from diábolos "accuser, backbiter, slanderer" + -ikos -ic entry 1 — more at devil entry 1

First Known Use

15th century, in the meaning defined above

Rhymes for diabolical

• follicle
• symbolical

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Kids Definition

diabolical

adjective

di·​a·​bol·​i·​cal ˌdī-ə-ˈbäl-i-kəl 

variants or diabolic

-ˈbäl-ik 

: of, relating to, or characteristic of the devil : fiendish

diabolically

-i-k(ə-)lē 

adverb

diabolicalness

-i-kəl-nəs 

noun