English Reference
adjective

synonymous

adj.
US /səˈnɑnəməs/ UK /sɪnˈɒnɪməs/ syn·ony·mous

  1. 01 B2 Upper Intermediate

    having the same or a very similar meaning as another word.

    having the same or nearly the same meaning as another word or phrase in the same language.

    Simple

    In many contexts, the word 'fast' is synonymous with 'quick'.

    In context

    Lexicographers often debate whether any two terms are truly synonymous or if subtle register differences always exist between them.

    Usage

    Usually follows the pattern 'X is synonymous with Y'.

    Pitfall
    The word 'big' is synonymous to 'large'. The word 'big' is synonymous with 'large'.

    Use the preposition 'with' after synonymous, not 'to'.

    antonymousopposite
  2. 02 B2 Upper Intermediate

    so closely connected with something that the two things seem the same.

    closely associated with or suggestive of a particular quality, idea, or brand.

    Simple

    For many people, the brand name has become synonymous with luxury.

    In context

    The politician's name became synonymous with corruption following the scandal, making a return to public office nearly impossible.

    Usage

    Often used to describe reputations or brand identities.

  3. 03 C2 Proficiency Technical Science

    describing a change in a gene that does not change the protein it makes.

    relating to a DNA substitution that does not result in a change to the amino acid sequence of the encoded protein.

    Simple

    A synonymous mutation usually does not affect the health of the organism.

    In context

    The researchers focused on synonymous substitutions to estimate the background mutation rate without the interference of natural selection.

    nonsynonymous

But as research over the past few decades has made clear, gender and sex are not synonymous .

The Conversation· 25 Aug 2026

The 30-year-old has 108 goals in 278 games for Villa after joining from Brentford for a then-record £28m and has been synonymous with Villa's rise of the past six years.

BBC News· 24 Aug 2026

From Medieval Latin synōnymus, from Ancient Greek συνώνυμος (sunṓnumos). By surface analysis, synonym + -ous.

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

This entry
Origin Ancient Greek συνώνυμος
Level B2 · Upper Intermediate
Frequency Frequent
Updated