diabolical

In real, traceable use. Part of the curated seed collection; community review is coming.

Sense 1

Meaning · English

(Devilishly) cunning or devious.

Register: slang

Where it’s used: Used American English
Sources & notes

Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).

Sense 2

Meaning · English

Crazy, wild (sometimes especially due to being unexpected or surprising).

Register: slang

Sources & notes

Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).

Common questions

What does “diabolical” mean?

(Devilishly) cunning or devious.

Is “diabolical” formal or informal?

diabolical is generally slang.