unfaithful

/ʌnˈfeɪθfl/ (bre, ipa) · [ənfˈeθfəl] /ʌnˈfeɪθfl/ (ame, ipa) · [ənfˈeθfəl] /ˌən-ˈfāth-fəl How to pronounce unfaithful (audio)/ (ame, mw)

unfaithful — adjective

  • unfaithfulpositive
  • more unfaithfulcomparative
  • most unfaithfulsuperlative

1. describes a married person or someone in a committed relationship who chooses to

1.形容詞B1
釋義

describes a married person or someone in a committed relationship who chooses to have sex with another person, thereby breaking the promise to be faithful

例句

Roya found a hotel receipt in her husband's pocket and realized he had been unfaithful.

pattern: discover + that + [person] + had been unfaithful

The therapist helped the couple talk honestly about why one partner had been unfaithful.

同義詞
  • cheating

    less formal; far more common in everyday speech

  • adulterous

    more formal and legal; specifically refers to married people

  • two-timing

    informal; implies active deception of two partners at once

反義詞
  • faithful

    keeps promises of romantic commitment

文法句型

unfaithful + to + person

discover + that + person + had been + unfaithful

用法筆記

Often used with 'to' followed by the betrayed partner. In everyday conversation, 'cheat on' is more common than 'unfaithful'.

常見錯誤

❌He was unfaithful his wife for years.
✅He was unfaithful to his wife for years.
💡'unfaithful' requires the preposition 'to' before the person betrayed.
❌I can't believe she unfaithful to him.
✅I can't believe she was unfaithful to him.
💡'unfaithful' is an adjective, not a verb; it needs a form of 'be'.

2. describes someone who does not keep promises or act according to the duties expe

2.形容詞B2
釋義

describes someone who does not keep promises or act according to the duties expected of them, such as a soldier who turns against their own country or a friend who reveals secrets

例句

The general was accused of being unfaithful to his country when he sold military secrets.

accused of + being unfaithful to + [country/duty]

A guard who is unfaithful to his duties might let dangerous prisoners escape.

同義詞
  • disloyal

    very similar; equally formal

  • treacherous

    stronger; implies active betrayal with harmful intent

  • faithless

    more literary or poetic; less common in everyday use

反義詞
  • loyal

    steadfast in supporting someone or something

  • faithful

    reliable in keeping promises

文法句型

unfaithful + to + duty/country/promise

用法筆記

Typically describes failure of serious obligations such as loyalty to one's country, employer, or sworn oath. Usually followed by 'to'.

常見錯誤

❌She was unfaithful to her diet again.
✅She broke her diet again.
💡'unfaithful' is too strong for small, personal commitments.
❌The dog was unfaithful to its owner.
✅The dog was disloyal to its owner.
💡'unfaithful' is not used for animal loyalty.

3. describes a copy, translation, record, or description that contains mistakes or

3.形容詞C1
釋義

describes a copy, translation, record, or description that contains mistakes or does not correctly represent the original thing it is based on

例句

This translation is unfaithful to the original poem because it changes the rhythm completely.

unfaithful + to + [original]

Historians rejected the document as an unfaithful copy of the original treaty.

unfaithful + [copy/translation/account]

同義詞
反義詞
  • accurate

    correct and exact

  • faithful

    closely resembling the original; used for reproductions

文法句型

unfaithful + noun

unfaithful + to + original

用法筆記

Cannot be used for mechanical failure or simple mistakes. Used before nouns such as 'copy', 'translation', 'account', or 'representation'.

常見錯誤

❌This watch is unfaithful.
✅This watch is inaccurate.
💡'unfaithful' is not used for mechanical devices that do not work correctly.
❌The unfaithful data ruined the study.
✅The inaccurate data ruined the study.
💡'unfaithful' is not used for numerical or statistical errors.