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 : extremely evil

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 of diabolical

• demonic
• sinister
• 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

Child labor in a Manchester factory is diabolical; child labor on a subsistence farm is helping out around the house. —Gideon Lewis-Kraus, New Yorker, 24 Nov. 2025

And to be forced to do it with multiple mouths to feed is nothing short of diabolical. —Essence, 20 Nov. 2025

From the constant looks that the contestants are serving and the thirst trap sizzle reels to the diabolical challenges and constant drama, The Traitors has a little bit of everything. —Michael Cuby, Them., 17 Nov. 2025

In fact, Anders calls it diabolical, which flips a switch in Hollis, who leaps to the wrong conclusion about his spin doctor. —Sophie Brookover, Vulture, 14 Nov. 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