unexplained

unexplained — adjective

1. describes something that happens or exists without anyone knowing or being able

1.adjectiveB2
Definition

describes something that happens or exists without anyone knowing or being able to say why it happened or what caused it

Example

The police are still looking into the unexplained death of a local fisherman.

collocation: unexplained death / disappearance / phenomenon

Élise noticed an unexplained red mark on her arm after the walk through the woods.

Common collocations
  • unexplained death
  • unexplained disappearance
  • unexplained phenomenon
  • unexplained event
  • unexplained occurrence
  • unexplained weight loss
  • unexplained symptoms
  • unexplained gap
  • unexplained absence
Synonyms
  • mysterious

    adds a sense of strangeness or secrecy; stronger emotional tone than unexplained

  • unaccounted-for

    specifically about people or things that are missing and cannot be found

  • unknown

    broader — can apply to anything not known, not just things lacking an explanation

  • inexplicable

    stronger — suggests the thing cannot be explained, not just that it hasn't been yet

Antonyms

Grammar Patterns

unexplained + noun

remain / go + unexplained

Usage Note

Frequently pairs with nouns like disappearance, death, phenomenon, or occurrence. Often follows remain or go to indicate an ongoing lack of explanation (e.g. 'the reason remains unexplained', 'the event went unexplained'). Distinguish from unexplainable: unexplained means 'not yet explained' (a cause likely exists but hasn't been found), whereas unexplainable means 'impossible to explain or understand'.

Common Mistakes

The cause of the fire remains unexplainable.' (when you mean it hasn't been found yet).
The cause of the fire remains unexplained.
'unexplained' means no explanation has been given yet; 'unexplainable' means it cannot be explained at all.
The disappearance was unexplainedly strange.
The disappearance was unexplained and strange.
'unexplained' is an adjective, not an adverb; the word 'unexplainedly' is non-standard.

Word family

Synonym discussion

Sense: adjective/1

All four words describe something that is not understood, but they differ in strength and focus. Unexplained is the most neutral — it simply states that no reason or cause has been given (e.g. 'an unexplained delay'). Mysterious adds an element of strangeness or secrecy that captures the imagination ('a mysterious figure appeared at the door'). Unknown is the broadest — it applies to anything not known, not just things lacking a causal explanation ('the author's identity remains unknown'). Inexplicable is the strongest — it suggests the thing is beyond human understanding and may never be explained ('an inexplicable fear of buttons'). Use unexplained when you expect an explanation may eventually be found; use inexplicable when you doubt one exists.

unexplained ↗mysterious ↗unknown ↗inexplicable

Common collocations

Nouns

Adverbs

  • as yet unexplained
  • still unexplained
  • largely unexplained
  • medically unexplained
  • otherwise unexplained

Phrases

  • remain unexplained
  • go unexplained
  • leave something unexplained

Prepositions

  • unexplained by

Etymology

LatinFrenchEnglish

Formed in English by adding the negative prefix un- (from Old English) to the past participle explained, which comes from the Latin verb explanare, meaning 'to make plain or clear'. The Latin word combines ex- ('out') with planus ('flat, level, clear'), so explained originally meant 'made flat' — like smoothing out a surface so everything is visible.