What is the difference between "undemonstrable" and "indemonstrable"? Indemonstrable has the meaning whereas the undemonstrable doesn't have. According to Google NGRAM both the words are widely used but Merriam webster or Oxford Dictionary doesn't provide the meaning. Ngram plot

Which word is correct "undemonstrable" or "indemonstrable"? Do they have same meaning?

EDIT: This is what I got when I searched in Merriam-webster. Merriam Webster screenshot

And for Oxford dictionary Oxford Dictionaries screenshot

  • 1
    Are you sure: merriam-webster.com/dictionary/indemonstrable
    – Cardinal
    Jul 2, 2016 at 11:16
  • undemonstrable: not able to be made evident. indemonstrable: incapable of being demonstrated or proved. Both have meaning.
    – user33000
    Jul 2, 2016 at 11:34
  • @Cardinal This is what I got in their website. Please have a look on the Question once again.
    – ARYF
    Jul 2, 2016 at 11:53
  • @ARYF I didn't mean you didn't search anything. I just want to mention MW has a definition. Perhaps I chose improper words bro.
    – Cardinal
    Jul 2, 2016 at 11:56
  • What you provided is for "indemonstrable" not for "undemonstrable". Anyway thanks. Do you know the reason behind this? Why popular dictionaries like them do not add this words?
    – ARYF
    Jul 2, 2016 at 11:58

2 Answers 2


Demonstrable just happens to be one of those words that doesn't have a well-established negating prefix (both un- and in- are used, with exactly the same meaning). But as this chart shows, native speakers don't much like either form - perhaps partly because of that uncertainty. We're much more likely to use alternative phrasing...

enter image description here

It may be worth comparing the full OED entry for...

enter image description here


enter image description here

Apart from the smaller number of citations, it may be significant that OED don't even bother to give the pronunciation for the latter (which has mostly been less common over the past two centuries).


The prefixes "in" and "un" are defined in most dictionaries. In both the Oxford and the American Heritage dictionaries they are both defined as "not or the opposite of". Therefore "undemonstrable" and "indemonstrable" mean the same thing. The only difference between "in" and "un" is that "in" can be used with "adjectives and words formed from adjectives" and "un" can be used with "adjectives, adverbs, verbs, and nouns".

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .