39 of the Best ‘Mysterious’ Synonyms and Antonyms

By Dr Oliver Tearle (Loughborough University)

The word ‘mysterious’ can be used to describe a wide variety of things: types of people, situations, or events can all be labelled ‘mysterious’. It means, broadly speaking, something that is the source of mystery, of course, and mystery is a word derived from the Latin mystērium which means ‘secret’.

Originally, the word referred to the secret rites of religious groups, as in the Eleusinian Mysteries. However, nowadays it’s more often used to refer to something whose meaning is secret or unknown.

What other ways are there to describe something that’s mysterious? Below, we introduce some of the best synonyms for the word ‘mysterious’, and say a little about the more noteworthy or curious synonyms on offer. We’ll conclude with some useful antonyms for mysterious.

‘Mysterious’ synonyms

Because mystery involves not being able to penetrate something, not knowing or understanding its meaning or the full story behind something, there are quite a few negative words ending in -able and -ible which the writer can draw upon.

So let’s start with a pair which, fittingly enough, signify that something which is mysterious cannot be explained: UNEXPLAINABLE and its perfect synonym, INEXPLICABLE.

Related words, also ending in -able or -ible and also taking a negative form, include UNACCOUNTABLE (cannot be accounted for), INCOMPREHENSIBLE (cannot be comprehended or understood), INSCRUTABLE and UNFATHOMABLE (cannot be determined or fathomed), UNKNOWABLE (cannot be known at all).

Whilst these are all near-synonyms for each other, and for mysterious, there are some important shades of difference between them: for instance, if somebody was uttering inane gibberish in a meeting, we might describe their talk as incomprehensible, but describing it as unknowable or unaccountable wouldn’t quite hit the mark.

ENIGMATIC is one of the strongest and most popular mysterious synonyms, since the meanings of the two words are pretty much interchangeable. So, although people prefer to talk of the enigmatic smile of the Mona Lisa, describing it as a mysterious smile would convey the same meaning.

Enigmatic is from an ancient Greek word which ultimately meant ‘fable’, but came to mean ‘to speak allusively or obscurely’. Of course, our modern idea of fables is wrapped up with this idea: a fable such as Orwell’s Animal Farm is allusive in that its meaning is not entirely clear to someone who doesn’t grasp that it’s an allegory about the Soviet Union.

Aesop’s fables are about animals but clearly their meaning points to human behaviour and morality rather than the (imagined) ethics of foxes or frogs. We tend to use the word enigma to refer to a riddle, whose meaning needs to be worked out because it is obscure. In other words, there is something mysterious, HIDDEN, or CRYPTIC about its meaning.

And cryptic literally means ‘hidden’ (again, from an ancient Greek word). It’s where the word crypt comes from, of course, because that’s a space hidden underneath a building, as well as the chemical element krypton, so named because its discoverers had to go to considerable lengths to uncover its existence: the element was, in a sense, hidden from view.

If something is mysterious, its meaning is hidden, so we might describe a person’s utterance as cryptic or a mysterious piece of writing as rather cryptic in nature.

As well as the various -able and -ible formations mentioned above, there are also several words ending in -ing which can serve as useful mysterious synonyms, such as PUZZLING, BAFFLING, MYSTIFYING, and PERPLEXING. All of these involve being foxed by the meaning of something.

Something that has us scratching our heads because it’s so mysterious might also be described as STRANGE, BIZARRE, CURIOUS or WEIRD. The word ARCANE is another useful synonym, though the meaning of this word is slightly more narrow, since it means ‘hidden’ or ‘concealed’. So mysterious knowledge that seems to be designed to keep the layperson from understanding it might be described as containing arcane knowledge.

RECONDITE is a word with a similar sense to arcane: it means OBSCURE or ABSTRUSE, i.e., something that is unintelligible, either by accident or deliberate design. DARK and VEILED can be used to denote the same thing.

These words are often used about kinds of knowledge or information. But what if a person is behaving in a mysterious way? They might be described as SECRETIVE, SURREPTITIOUS, FURTIVE, EVASIVE, or CAGEY: all words which imply the person is being deliberately mysterious because they’re trying to conceal their actions from discovery.

The word COVERT (literally, ‘covered’) is similar, although it can be used about operations which are deliberately done in secret, e.g., by the police so that they can gather evidence about a crime scene. Indeed, covert operation is a common police phrase.

DISCREET is also more neutral than the words listed at the start of the preceding paragraph. Indeed, someone can be discreet because they’re being diplomatic and tactful and don’t want to hurt someone’s feelings.


This is not as strong a synonym for mysterious as the other words listed above, but the meanings of the words overlap sufficiently to warrant inclusion here. Note the spelling: discrete things are separate and different; discreet people try to avoid unwanted attention.

‘Mysterious’ antonyms

It’s easy enough to come up with some common antonyms for mysterious: in light of the numerous negative un- and in- prefixed words listed above, it stands to reason that the antonyms would simply be those words with their negative prefixes removed.

Sure enough, we have EXPLAINABLE, EXPLICABLE, COMPREHENSIBLE, INTELLIGIBLE, and KNOWABLE, all perfectly good antonyms for mysterious (KNOWN can be used as well as knowable).

UNDERSTOOD and STRAIGHTFORWARD also capture the opposite meaning to mysterious: if something is understood, there is no mystery remaining, and if it’s straightforward it’s unlikely to be obscure enough to create any mystery.

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