Is there a pair of words in English, where one is a grammatical negation of the other, but they are synonyms?
For the negation I'm thinking about a negative prefix or suffix, like de-, dis- or -less, but it can also be built in other way.
For example for the word 'likely' the hypothetical pair would be 'likely' and 'unlikely' and they would mean exactly the same (i.e. 'likely').
This came to my mind because there are at least two such pairs in my native language.

Edit: IMO this is not a duplicate of auto-antonym. The auto-antonym examples from the linked pages don't meet my criteria. However I was unaware that list questions are automatically "too broad". Thanks Andrew Leach for explaining me that, I think I will try a community wiki question then.

  • See auto-antonym
    – Mitch
    Feb 17, 2015 at 15:05
  • 1
    List questions are automatically "too broad", although you might get away with a community wiki question, especially when there aren't many answers. Such pairs undoubtedly exist and flammable and inflammable is the most obvious pair. See this related (but opposite) question too.
    – Andrew Leach
    Feb 17, 2015 at 15:06
  • @tchrist These are not auto-antonyms (discussed in the linked question). He is seeking pairs of different words that mean the same thing, one of which is constructed from the other using a negation suffix.
    – bib
    Feb 17, 2015 at 15:12
  • 2
    On chat, RegDwigнt suggested (un)ravel. That might be a better example, since the in- in inflammable is not a negator. (It doesn't seem that any of the examples on the auto-antonym list answer this question, so I don't believe it should be a duplicate.)
    – user28567
    Feb 17, 2015 at 15:16

1 Answer 1


Flammable and inflammable

Oxford Dictionaries Online

  • Inflammable does not fulfil the condition 'ha[ving] the same meaning as its negation', as in- is not the negating prefix here. Feb 17, 2015 at 15:34
  • @EdwinAshworth The difficulty is that in any term in which the root is preceded by a traditional negation suffix, that suffix will not work as a negation in the particular case if the terms actually are opposites.
    – bib
    Feb 17, 2015 at 15:57
  • I don't understand why people ask questions like this here. The potential future usefulness to readers in general versus effort needed imbalance is colossal. Yes, I find them interesting, like anagrams and (other) cryptic clues, but ELU isn't intended for them. Feb 17, 2015 at 16:56
  • @EdwinAshworth I get closing it for that reason or the inclination against lists, but not because it's a duplicate. And I meant prefix, not suffix.
    – bib
    Feb 17, 2015 at 17:48

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