“Undistinguishable” vs. “indistinguishable”

Question

Is there a difference between these two words? To me, it seems that undistinguishable is more where you can't tell what it is, and indistinguishable seems to be where they're the same. It seems a lot of places list them as synonyms though.

Answer 1

I'm a native English speaker, and I've never heard of "undistinguishable". I searched for undistinguishable and Google replied with:

Did you mean: indistinguishable

Princeton University's WordNet defines indistinguishable as:

• identical: exactly alike; incapable of being perceived as different; "rows of identical houses"; "cars identical except for their license plates"; "they wore indistinguishable hats"

• not capable of being distinguished or differentiated; "the two specimens are actually different from each other but the differences are almost indistinguishable"; "the twins were indistinguishable"; "a colorless person quite indistinguishable from the colorless mass of humanity"

To convey the sense of "you can't tell what it is", you could use indecipherable or inscrutable.

Answer 2

I've never seen "undistinguishable" before. My spell-check flags it as an error and suggests "indistinguishable". I suspect it's a typo or a case of misspelling a word in a logical way. I can't imagine that its meaning would be different from "indistinguishable". The Corpus of Contemporary American English (COCA) lists only 8 hits for "undistinguishable" and 1000+ hits for "indistinguishable". I'd stick to the latter.

Answer 3

Bleak house By Charls Dickens :

As much mud in the streets as if the waters had but newly retired from the face of the earth, and it would not be wonderful to meet a Megalosaurus, forty feet long or so, waddling like an elephantine lizard up Holborn Hill. Smoke lowering down from chimney-pots, making a soft black drizzle, with flakes of soot in it as big as full-grown snowflakes--gone into mourning, one might imagine, for the death of the sun. Dogs, undistinguishable in mire. Horses, scarcely better; splashed to their very blinkers.

Answer 4

"Undistinguishable" may perhaps be used only regionally now, I have heard it a lot in my life, but I am from western North Carolina, where Standard English is rarely spoken. It may not be part of contemporary Standard English. Etymonline has an entry for it, listing it from the 1580s meaning 'not distinguishable'.

Answer 5

These things seem small and undistinguishable,
Like far-off mountains turned into clouds.

Unless you want to be fussy, in which case:

These things seeme small & vndistinguishable,
Like farre off mountaines turned into Clouds.

William Shakespeare, from Act IV, Scene 1 of A Midsummer Night's Dream.