It’s my favorite Hebrew word.
It used to be dope in the mid tens (or is that teens?)
I’ll throw in one French an one Italian:
Déshabillé. When checking the spelling, I see it has been pilfered by English, but the explanation does not match the original.
the state of being only partly or scantily clothed.
“the paintings of Venus all shared the same state of déshabillé”
I’d say its proper use would be like disheveled but in a fashionable way.
Speaking of fashion
Sprezzatura. A close relation to déshabillé and traced back to 1528 it means “a certain nonchalance, so as to conceal all art and make whatever one does or says appear to be without effort and almost without any thought about it”
And if that doesn’t describe Italian fashion…
This is the first pic Google gave me for sprezzatura:
“But I’ll be true to the song I sing and live and die a pirate king Mayor!” 
There are odd exceptions, of course. “Está muerto” comes to mind.
I don’t know if it has the same connotation in German, but the Yiddish word Mensch cannot really be translated into into English. It implies an unusual degree of humanity. Can a German speaker tell me if it has the came meaning in German?
Schadenfreude, meaning finding joy in someone else’s misfortune has of course been borrowed into English for want of a suitable native English term.
I have an actor friend who jokes that, if you ever forget your line in a play by the Bard, you should just say “We shall speak of this anon,” and walk off.
I’ve always liked the Danish word hygge, which I’ve heard described as “the feeling of contentedness and coziness you feel sitting by the fire on a cold night, with friends gathered ‘round and a hot drink in your hands.”
Not exactly in the same sense as in Yiddish, but to a degree. “Mensch” foremostly just means “human being” in a neutral way, but if someone tells you “Sei doch Mensch”, they tell you to be humane. The adjective “menschlich” can mean both human and humane.
The German word “gemütlich” (corresponding noun “Gemütlichkeit”) connotes the same idea.
A few months ago my department started talking about arbejdsglæde. Sounds like a good thing, especially since most of us spend so much time at the workplace.
There’s no word for “relative”?
I’m sure there is a word for “relative” or perhaps there are multiple words , none of which means exactly what the English word "relative " means to native English speakers. Which is what is usually meant when people say that it’s difficult to translate certain words from one language to another - it almost never means that an idea can’t be expressed in one of the languages, it’s almost always a matter of it taking more words to express exactly the same amount of information in one language than the other. For example, in some languages with grammatical gender, you can’t easily distinguish between a group of males and a mixed group - “my sons” and “my children” use the same words as long as one of those children is a son. In some languages, you must distinguish between your mother’s sister, your father’s sister, your mother’s brother’s wife and your father’s brother’s wife - all of which would be “aunt” in English. And “relative” might not work, because in some cultures your mother’s sister , etc, is not a your relative. Even if “relative” does work, it includes many relatives other than the four kinds of aunt. ( or eight kinds of aunt - “mother’s older sister” and “mother’s younger sister” can be different words.)
The word “relative” will mean different things to different native English speakers too. The point is exactitude doesn’t matter, because, guess what, we are all translating what we think we heard into what we think it means according to what we think the other person meant, even if we are speaking a common native language.
Yes, there is a word for “relative” in Chinese, but it’s very vague - not at all as specific as “cousin” - which could be problematic in a situation where you really need to specify clearly that someone is a cousin and not an aunt, uncle, grandparent, nephew, etc.
How specific is “cousin” in English? What does it mean exactly, and for all native English speakers?
One of my favorite untranslateable German words, that is sooo useful these days: Backpfeifengesicht, “a face that’s badly in need of a fist.”
Why not just “punchable”?
In U.S. English, “cousin” means a child of one of your parent’s siblings. The son or daughter of your father’s brother or your mother’s brother, etc.
In many families these will be people of roughly your own generation that you’ll see throughout your childhood (whenever your parents visit their siblings), and maybe throughout your life.
That’s what “cousin” means 98% of the time. It can, like most words, have niche or metaphoric meanings.
OP here.
Is there a word for people who can find something to argue about in any simple statement? 
Doper?
Sure, German to your help: Korinthenkacker, literally raisin shitter, meaning an extreme nitpicker/pedant. So, all of us. 
For us, it also extended to second and third cousins, as well. Also, kin of very close family friends. I know you disclaimed it with niche and metaphorical meanings, but I don’t think the first is that unusual, i.e. cousins do not necessarily only indicate first cousins.