I seem to recall encountering a language in which this fun translation occurred, but it’s a difficult question to Google.
Does anyone know of any word-pair that has a positive meaning in one language and a negative meaning in another?
Daniel
One example is “Gift”, which means poison in German, and another thing in the closely related language English.
In Greek, the word for no is pronounced Neh and sounds a lot like Nay! “No way” is O Shee which to me can sound like OK.
I know on tv, there’s been many (not funny) jokes made about how kids say “bad” when they mean “good”.
Coincidentally, bad means ‘bad’ in Persian. It’s even pronounced with the same short vowel [æ] as in English. And the Persians had the word first; we must have copied from them.
I don’t know in which language bad means ‘good’, but there is plenty of other language fun along those lines…
Catalan alt 'high - ’ Turkish alt ‘low’
Dutch beter ‘better’ - Turkish beter ‘worse’
English black - Old Chinese bhlak ‘white’
Mongolian bog ‘demon’ - Russian bog ‘god’
Kashmiri ded ‘grandmother’ - Russian ded ‘grandfather’
English he - Hebrew hi ‘she’
Coptic i ‘come’ - Latin i- ‘go’
Mongolian ir- ‘come’ - Spanish ir ‘go’
Hebrew ish ‘man’ - Jacaltec Mayan ish ‘woman’
English lumbar (back) - Pashto lumbar ‘front’
English mama ‘mother’ - Georgian mama ‘father’
English nay ‘no’ - Greek nai ‘yes’, Korean ne ‘yes’
Basque ni ‘I’ - Chinese ni, Tamil ni* ‘thou’
English no - Hawaiian no affirmative
English papa ‘father’ - Old Japanese papa ‘mother’
Arabic dialect rah ‘go’ - Hindi rah ‘stay’
Hindustani rog ‘disease’ - Pashto rogh ‘healthy’
English sad - Turkish sad ‘happy’
English server ‘one who serves’ - Ottoman Turkish server ‘one who rules’
Italian si ‘yes’ - Swahili si negative
Arabic su’ ‘evil’ - Sanskrit su- ‘good’
Basque su ‘fire’ - Turkish su ‘water’
Malay tak ‘no’ - Polish tak ‘yes’
French toi ‘thee’ - Vietnamese tôi ‘me’
Mordvin tol ‘fire’ - Nivkh tol ‘water’
Mayan yum ‘father’ - Tibetan yum ‘mother’
Italian va ‘go!’ Tamil va ‘come!’
If we find out the answer to the OP, it would make a good addition to this list.
In Czech, “no” means “yes.” It’s the short form of “ano.”
In French, “blesser” is the verb “to injure”.
I don’t know if there is, but if you found it, it would be wicked. 
“Wicked” was the best example I could think of on my own, but I hoped someone out there could come up with better (beter?) examples than mine. Y’all have not disappointed–these are great!
I ask because of this: this list of words will help me shred Masaru Emoto’s claims from the movie.
Daniel
I can’t think of any examples from Japanese (at the moment at least.)
I don’t know what claims the movie makes, let alone what that has to do with whether bad means good in some language. But just as it is interesting and potentially relevant I would point out the Chinese practice of giving their male children girls names to last them through their youth. This is because girls are nasty and demons won’t bother them–thus the boy will be safe until he is strong enough to handle demons.
If I told my next door teenage neighbor that I thought his car was “the shit” he would think it was “good”.
If I told my 68 year old father that his car was “the shit” he would think it was “bad”.
The English word " bad" means bath in Dutch.
And don’t forget words that have totally opposite meanings within the same language, depending on context. Like " bitch" “screw” " fine" " kid" . Or Joke and yolk.
Or words that have different meaning when pronounced different. Is that crystal forming water supposed to have ears?
Then there’s the made-up tale of a minor league baseball team whose equipment trailer caught fire on the road. By the time help arrived, everything was lost, but two kinds of gear were still the same. The burnt cork the players put under their eyes was still burnt cork, and the ash (wood) bats were still ash.
This may be a bit of a long shot, but the Japanese word for ‘no’ is iie, which sounds a teeny little bit like ‘yeah’.
Dunno if you’re seriously proposing that, but www.etymonline.com states its etymology is unknown for certain, and speculates it came from an Old English word for an effeminate man, hermaphrodite, or pederast.
Unless it’s prem-rog - which is lovesickness. 
I know, I’ve examined that etymology and found it wanting. That was years before I developed into a bæddel girl myself. The explanation just sounds too farfetched and too dependent on transphobia. Besides, there’s no explanation offered for the origin of bæddel, so it still isn’t much of an explanation. If the world is held up by an elephant, what holds up the elephant? Then we have to find a turtle for the elephant to stand on, etc. So I gave this etymology a lot of consideration, but it just makes my Occam’s Razor-o-Meter go off, and I pronounced it overly farfetched. Ask yourself: are you convinced by that?
The history of transgender and transphobia, especially in the Middle Ages, is tangled and controversial. Leslie Feinberg published a study, Transgender Warriors, connecting the practice of gender-crossing among mediæval peasants with peasant revolts against the lords, citing several cases in which the two were correlated. So according to Feinberg, gender-crossing took on political significance in the Middle Ages. The use of a pejorative specifically targeted at gender variant people may be a lexical remnant of political strife a millennium ago. Can anyone quote the context of these Old English pejoratives? What was the motivation of an author using the words this way?
The American Heritage Dictionary, whose etymologies I have consistently found the most reliable, does not trace bad any further back than Middle English badde. They recognized the bæddel theory for the flimsy speculation it is.
My own hypothesis runs like this: The original etymon *bæd- meant generally the opposite of good, as it does today. It may have been a word spoken in a low prestige dialect or argot, which would explain why it wasn’t recorded by King Alfred’s scribes as such. Standard, literary Old English used ful (>foul) to mean ‘bad’ in the general sense. Maybe some Rush Limbaugh of Anglo-Saxon times wanted to propagandize against gender variant people, and coined a new pejorative bædling: took the low-class word *bæd- and added the regular attributive ending -ling (which survives in words like Earthling; it was used much more frequently in Old English), or the diminutive ending -el (frequently used in Yiddish to this day, bubbeleh). Diminutives can be either endearing (as in bubbeleh) or pejorative (as in bæddel). Who knows, bæddel might have originated as an endearment by someone with a tranny lover, but then was twisted by a satirist into a pejorative mockery. Anyway, this derivational path makes more sense to me than bæddel just appearing out of nowhere and then changing to a completely different meaning in some obscure way.
Old English, in my reckoning, got the word from Proto-Indo-European *bhadh- ‘hurt, sicken, repel, nauseate’. Whew! Is that bad enough for you? Related forms of this root included *bhoidhos ‘horrid; horror’ and *bhodh- ‘pang, pain’. Cite: Stuart E. Mann, An Indo-European Comparative Dictionary (Hamburg: Buske Verlag, 1984), 59, 88, 89. Mann also cites Julius Pokorny, Indogermanisches Wörterbuch II, 130
Words derived from this root include Sanskrit भाधा bhādhā ‘pain’; Lithuanian bodau ‘tired, bored’, bodus ‘nauseating’; Latin foedus ‘foul, horrible’; Latvian baida ‘fear, horror’; Old Church Slavic bĕda ‘hardship’; and possibly Greek πηθω pēthō ‘suffer’. What’s more, I would derive Persian bad from the same root, making it not a coincidence but a cognate with English bad.
Linguists will recognize that *bhadh- > *bæd- strictly observes the laws of sound correspondence from Proto-Indo-European into Germanic: *bh- > b-, *a > æ, *dh- > d-. So what do you think, Doper linguists? Have I nailed it?
BTW, someone should update etymologists that the term hermaphrodite for people with ambiguous genitalia or anomalous chromosomes is now considered obsolete. We now say “intersexed.”
Back to the OP: etymonline.com says in their entry on bad: “Ironic use as a word of approval is said to be at least since 1890s orally, originally in Black Eng., emerging in print 1928 in a jazz context.” Hey, thanks for the link, yBeayf. Here’s another one for the OP: The Proto-Indo-European root *bhodh- ‘pain’ has a homonym *bhodh- ‘good’. You’re really onto something here, Daniel!
The Hebrew word for she is he. And the Hebrew word for he is hu (ie, “who”). And the word for who is mi (ie, “me”).
These coincidences are more funny than they are confusing, honestly.
I agree, it looks like grasping at straws. I was just questioning your implication that English had borrowed the word from Persian.