# mysterious

/mɪˈstɪɹiəs/ (US) · /mɪstˈiəɹɪəs/ (UK)

Source: https://englishreference.com/word/mysterious
Updated: 2026-06-19

## Senses

### 1. strange and unknown

adjective · CEFR B1

strange, unknown, or difficult to understand or explain.

For teachers: relating to or being a mystery; difficult or impossible to understand, explain, or identify.

- A mysterious light appeared in the sky late last night.
- The detectives were baffled by the mysterious disappearance of the painting, as the security alarms had never been triggered.

### 2. secretive behavior

adjective · CEFR B2

behaving in a way that shows you are keeping a secret.

For teachers: deliberately enigmatic or evasive in behavior or speech, often to provoke interest or hide information.

- He was being very mysterious about where he went last weekend.
- She gave him a mysterious smile and refused to say another word about her plans for the upcoming merger.

Usage: often used to describe a person's expression or tone of voice

## Examples

- A mysterious man left a letter at the door.
- The detective spent years trying to solve the mysterious disappearance of the local baker.
- The ancient ruins were covered in mysterious symbols that had baffled archaeologists and linguists for over a century.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.