enigma

enigma — noun

1. Something that is puzzling, mysterious, and very difficult to make sense of — fo

1.nounB2
Definition

Something that is puzzling, mysterious, and very difficult to make sense of — for example, a strange event, an unsolved question, or a complicated situation that seems to have no clear answer.

Example

Why Aoi's grandfather locked his study before leaving was an enigma to his family.

why-clause as subject: 'Why [person]... was an enigma'

The disappearance of the old temple bell remains an enigma no one has explained.

collocation: remain(s) an enigma

Common collocations
  • remain an enigma
  • the enigma of something
  • be an enigma to someone
  • complete enigma
  • total enigma
  • solve an enigma
Synonyms
  • mystery

    More general and common; any unexplained thing, from a crime to a strange event

  • puzzle

    Suggests something designed to test cleverness or a problem with a solvable answer

  • riddle

    Implies a question or statement with a hidden meaning, often playful or verbal

  • conundrum

    A tricky problem with a paradoxical or clever element; similar register to enigma

Antonyms

Grammar Patterns

enigma + of + noun phrase

why/how-clause + be + an enigma

Usage Note

Common in formal, literary, or journalistic contexts. In everyday conversation, 'mystery' is more frequent. Often appears in the structure 'the enigma of + [noun phrase]' (e.g. 'the enigma of human consciousness').

Common Mistakes

The math problem was an enigma to me.
The math problem was a mystery to me.
'enigma' suggests a deeper, almost philosophical quality of being unfathomable; 'mystery' is more natural for everyday puzzles and problems.
He solved the enigma in five minutes.
He solved the riddle / puzzle in five minutes.
'enigma' implies something that resists quick solution; using it with a short time frame feels unnatural.

2. A person who is difficult to understand or figure out because their thoughts, fe

2.nounC1
Definition

A person who is difficult to understand or figure out because their thoughts, feelings, or behaviour are hidden, changeable, or unpredictable.

Example

Even after years of working together, Élise remained an enigma to her colleagues.

remain an enigma to [someone]

The writer was something of an enigma — he rarely gave interviews or appeared in public.

something of an enigma (fixed phrase)

Common collocations
  • be an enigma
  • remain an enigma
  • something of an enigma
  • an enigma to someone
Synonyms
  • puzzle

    Less formal; can describe someone whose behaviour is baffling but less profound

  • closed book

    Idiomatic and informal; suggests someone who refuses to share personal information

  • mystery

    More common but less specific; can apply to anyone unknown or secretive

Antonyms
  • open book

    Someone whose thoughts and feelings are easy to read

Grammar Patterns

be an enigma

remain an enigma to [someone]

something of an enigma

Usage Note

When applied to a person, 'enigma' suggests that even people who interact with them regularly find them hard to read. The fixed expression 'something of an enigma' is common in both formal and neutral registers. Unlike 'mystery person', 'enigma' carries a slightly intellectual or admirable tone.

Common Mistakes

He is a secret enigma.
He is an enigma.
'secret' is redundant because being enigmatic already implies hidden qualities.
She is an enigma person.
She is an enigma.
'enigma' already functions as a noun meaning a person of this type; adding 'person' is ungrammatical.

Word family

  • enigmatic
    adjectiveB2
  • enigmatically
    adverbC1
  • enigmatist
    noun

Synonym discussion

Sense: noun/1

All four words describe something hard to understand, but with different nuances. 'Mystery' is the broadest and most common word — it can refer to any unknown or unexplained thing, from a crime to a strange event, and works in both everyday and formal contexts. 'Puzzle' suggests something designed to test cleverness (like a crossword or logic game) or a problem with a known solvable answer. 'Riddle' implies a question or statement with a hidden meaning, often playful or verbal, and typically has a solution once you figure out the trick. 'Enigma' is more formal and literary than the others; it suggests a deeper, almost philosophical quality of being unfathomable — not necessarily something you can solve. 'Conundrum' is a tricky problem with a paradoxical or clever element. Use 'mystery' for everyday situations ('the mystery of the missing keys'), save 'enigma' for things that feel profoundly puzzling ('the enigma of human consciousness'), and reach for 'riddle' or 'conundrum' when wordplay or a logical trick is involved.

mystery ↗puzzle ↗riddle ↗conundrum

Common collocations

Nouns

Adverbs

Phrases

  • remain an enigma
  • be an enigma
  • something of an enigma
  • solve the enigma
  • the enigma of

Prepositions

Etymology

GreekLatinFrenchEnglish

The word 'enigma' came into English in the 1500s from Latin 'aenigma', meaning 'a riddle', which itself came from Greek 'ainigma' (αἴνιγμα), meaning 'dark saying, riddle'. The Greek root 'ainissesthai' means 'to speak in riddles', and traces back to 'ainos', a word for a fable or story with a hidden meaning. So from the beginning, the idea of something hidden or obscure has always been at the heart of the word.