# Term for words that seem like opposites but actually mean the same thing?

**URL:** <https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367>\
**Category:** Factual Questions\
**Created:** [September 11, 2020, 8:14pm UTC](https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367 "2020-09-11T20:14:56Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\
**Post date:** [September 11, 2020, 8:14pm UTC](https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367/1 "2020-09-11T20:14:56Z")

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Is there a term for words that seem like they should be opposites, but are actually synonyms?

Examples:

flammable/inflammable  
habitable/inhabitable  
valuable/invaluable  
bar/debar  
terminate/exterminate  
void/devoid

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [September 11, 2020, 10:58pm UTC](https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367/2 "2020-09-11T22:58:32Z")

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False Antonyms or Pseudoantonyms.

As opposed to _Sanction_, which is an Autoantonym (it means the opposite of itself)

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**Author:** ![yearofglad](https://avatars.discourse-cdn.com/v4/letter/y/b782af/32.png) [@yearofglad](https://boards.straightdope.com/u/yearofglad)\
**Post date:** [September 11, 2020, 11:19pm UTC](https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367/3 "2020-09-11T23:19:29Z")

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Now that the OP has been answered:

I’ve never heard the term “autoantonym” but have heard words like _sanction_ and _cleave_ referred to as contranyms (although autoantonyms makes sense as well).

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**Author:** ![MandaJo](https://avatars.discourse-cdn.com/v4/letter/m/ac91a4/32.png) [@MandaJo](https://boards.straightdope.com/u/MandaJo)\
**Post date:** [September 12, 2020, 2:02am UTC](https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367/4 "2020-09-12T02:02:40Z")

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“Dust” is another

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**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\
**Post date:** [September 12, 2020, 7:26pm UTC](https://boards.straightdope.com/t/term-for-words-that-seem-like-opposites-but-actually-mean-the-same-thing/920367/5 "2020-09-12T19:26:11Z")

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When I was growing up the word was “inflammable”, capable of being inflamed. Too many people took the “in” as negation and so “flammable” became standard in the interests of safety. But now, “inflammable” was ambiguous. What used to be “non-flammable” is now generally rendered as “inflammable”, although I think “non-flammable” would be clearer, given this history.

“Cleave” is not really a contranym (the word I am familiar with). It is two words with different origins and etymologies that, after sound changes, have fallen together. The first one, cleave, cleaved, cleaved means put together and I think is likely cognate with glue and collate. The other, cleave, clove, cloven (or cleft) means to separate. I think a garlic clove is a piece separated from the head.