English Reference
adjective

erroneous

adj.
US /ɛˈɹoʊniəs/ UK /ɛɹˈəʊniəs/ er·ro·neous

  1. 01 C1 Advanced FormalAcademic

    wrong or based on a mistake.

    containing or derived from an error; inaccurate or based on a false premise.

    Simple

    The newspaper had to apologize for the erroneous information in yesterday's report.

    In context

    The researcher's conclusions were ultimately found to be erroneous because the initial data set had been contaminated during collection.

    Usage

    Usually placed before the noun it describes.

    Teacher's tip

    Learners often use 'wrong' or 'incorrect' in every situation; 'erroneous' is a high-level alternative for formal writing, especially when discussing logic or data.

  2. 02 C2 Proficiency TechnicalFormal Law

    describes a legal decision that follows the rules but is still wrong in some way.

    deviating from the specific requirements of the law while still maintaining legal authority; not necessarily void or illegal.

    Simple

    The judge's ruling was considered erroneous, but it remained in effect until the appeal.

    In context

    The appellate court determined that while the lower court's procedure was erroneous, the error did not significantly prejudice the outcome of the trial.

    Teacher's tip

    This is a highly specialized legal sense. In general English, the word simply means 'wrong'.

    procedurally flawed

It becomes a lot tougher if mum or dad is being fed mixed and erroneous messages about the benefits and harms of vaccination.

The Guardian· 20 Aug 2026

From late Middle English erroneous, from Middle French erroneux, from Latin erroneus.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin erroneus
Level C1 · Advanced
Frequency Frequent
Updated