We hope your vocabulary study is progressing smoothly, but we’re sure that you’ll encounter some fiendishly difficult words now and then. You might even be faced with the cruel reality of a deadline, as test dates approach or presentations are rescheduled. The devil is in the details, as they say, and each piece of knowledge you gain about a word will contribute to a solid foundation in the English language.

Today we’re looking at the word diabolical, which means “extremely cruel or wicked.” As you might imagine, this adjective can be traced back to the Greek word diabolos, which is also where we get the English word devil. Another word for devil is fiend, hence the word fiendish.

Example: The evil genius spent weeks in his underground laboratory, working on his diabolical plan to enslave humanity by adding subliminal messages to television broadcasts.

Diabolical and cruel are synonyms, but in general we use diabolical when we’re talking about something or someone who acts deliberately, with intelligence (though not with compassion). We call a cat cruel when it seems to get pleasure out of tormenting a mouse before killing it, but there’s no evidence that the cat is doing this with the thought of causing pain. A particularly harsh winter is often called cruel when it causes plants and animals and people to suffer and die, but as far as we know there’s no guiding mind behind a blizzard. In either case, unless you were speaking metaphorically, you wouldn’t use diabolical to describe the cat or the winter.

Interestingly, the word wicked, which started out as another way to say diabolical (from the Old English word wicca, or “sorcerer,” someone often accused of working with devils) is now in current use as an adjective meaning “extremely good” – the opposite of its original sense of “extremely bad!”

Words and their meanings and use may change over time, but one thing remains the same: the work you put into your English vocabulary study program will pay off in the end.