Asklemmy

Hebrew has a non-insult that sounds like an insult - "In your mother". It's not a polite phrase, mind you, but it's not usually used directly as an insult. It has many varied uses. it can be a shorthand for "Swear on your mother's life", mainly to express doubt (ex. "Dude, I won first prize in the lottery!" "really? In you mother!?") or a plea ("I really need a ride right now. In you mother, could you come pick me up?"). It can also be a modifier to "leave me alone", where "leave me in your mother" has about the same meaning as "leave me the fuck alone"/"fuck off".

Despite being half Cypriot, I don't speak much Greek. Apologies to actual Greeks who realize how badly I'm butchering my transliterations here; my ancestors would be ashamed. (Most of them would probably just laugh at me though.)

That said, one of the funnier ones that used to go around in my family works like this: You yell for me from across the house. I respond "Di?" ("What?") And you yell again, usually meaning I should come over to wherever you are. Again, I say, "Di?" ("What?") And in exasperation, you respond, "Si kephali su tribidi!" (Your head is full of holes!) with emphasis on the last, matching, syllable as if to say "that's what!"

Swedish Skitstövel - shit boot, basically means asshole

Not in my language but it my local dialect "va' in mona" or "va' in figa" both translate to "go to (fuck a) p***y" and are short forms of

Va' in figa to' mare

which suggests the listener should go fuck his own mother's p***y. Very common insult in north-eastern Italy with no equivalent even in standard Italian.

Li mortacci tua!