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

Made for those looking for slice-of-life calm with dramatic bite, Shoshimin combines deliberate pacing and a contemplative, off-kilter character study with some amusingly diabolical scheming. —Kambole Campbell, Vulture, 9 Dec. 2025

With a story of secret cabals and a child born to rule, Dumont projects the nasty prejudices and bureaucratic rigors of local politics, the tangles of family allegiances, and the tender grunge of young lust into divine and diabolical clashes run from celestial and subterranean castles. —Justin Chang, New Yorker, 5 Dec. 2025

And the video, showcasing a diabolical Santa holding Flowers hostage in the desert while gleefully digging his grave. —Melissa Ruggieri, USA Today, 4 Dec. 2025

What made this Journey so diabolical is there was a time limit on Steven going all around the perimeter of the island to collect combination lock puzzle numbers, but the player had no idea what the time limit was. —Dalton Ross, Entertainment Weekly, 4 Dec. 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