Asklemmy

"Κλάσε μου τα αρχίδια" which literally stands for "fart my balls" in Greek.

It's a way of telling someone to go fuck himself.

Not my native language but the German language has some pretty fantastic words/insults like "punchable face" (backpfeifengesicht) and "brain denier" (gehirnverweigerer).

German: "Du Lappen"

Translates to "You rag", pretty much calling someone a loser or idiot.

"mange tes morts" in french, can be translated to "eat your deads" which is like go fuck yourself

Brazilian portuguese tends to lack impactful phrases, but is full of single curse words. A big portion of them a clear example of how much negative bias there is culturally against certain groups (gay men, women in general, disabled), unfortunately :/

One that isn't often used, but that I almost always laugh loud whenever I hear, is "Enfia uma dentadura no cu e sorria pro caralho", which roughly translates into "Stick a denture up your asshole and smile at the dick". For when simply saying "go fuck yourself" isn't enough.

Băga-mi-aș pula-n coliva mă-tii de să-mi sară coaiele din bomboană-n bomboană

This is a highly niche one in my native language as well, as one must also know what is colivă - it's basically a desert that we eat at funerals with m&m-sized candies in it as well. So it roughly translates let me stick my dick in your mother's coliva so hard that my balls jump from candy to candy

Altough it's more like a "gypsy curse", but there's one that translates to sth like "I wish you'll having ten rings but none fingers"

Not that it’s untranslatable, but I enjoy it quite a lot.

Поцілуй бузька в калатало - go kiss a stork on the knocker.

If you ever heard storks, you’ll recognize the dismissiveness of this statement.

Not really an insult but:

"Hänellä ei taida olla kaikki muumit laaksossa"
"They don't seem to have all moomin in the valley"

When someone is talking crazy, etc

Gea mor net af die Kondl. "Don't step on my milk jug". You're annoying me and you better shut up or go away.

Konnsch mor in Buggl oirutschn. "You can slide down my back". I don't give a fuck.

German dialect from Tyrol.

German Korinthenkacker (currant shitter) is someone who tries to win an argument by looking at unimportant details.

That's not exact:

• Me cago en tus muertos = I shit on your ancestors / I shit on your dead relatives.
• Me cago en todos tus muertos = I shit on all of your ancestors / I shit on all of your dead relatives.

And in the theme of insults from Spain, a loaded one is also: Me cago en tu puta madre = I shit on your fucking mother / I shit on your whore mother

See, the thing with "puta/puto" is that it literally means "whore", but it's used to empathize cursings just like "fucking" is used in english. We're even misusing it by putting it before verbs, imitating it's use in english.