What are some insults in english that will make non-native speakers have to ask someone their meaning?

Dipshit. It's my favorite insult. If you call a man an asshole or fucker, many take it as a sign of strength or say, 'i just tell it like it is." Dipshit is stupid and juvenile and naive and just perfectly describes so many people.
- Oh, that's why I like "dipshit" so much. Now I understand myself better, thanks!

He'd peel an orange in his pocket
He has two brains cells and they're both fighting for third place
He's a face like he's trying to eat an apple through a tennis racket
The tide wouldn't take her out
Scarlet for your mam for having you
Your arse is jealous of your mouth
Snipers dream
Spanner
- I am a native English speaker and had to Google "peel an orange in his pocket". It does not mean what I assumed.
  
  Non native speaker here and is the only of the 2 I didn't get. Spanner is the other one.
  
  What did you think it meant?
  I did have to think about it like, context helped.
- I've never heard a single one of these
  
  I've heard about half.

Your father smells of elderberries.
- "Your mother was a hamster!" is pretty self-explanatory though.
  But elderberries smell rather nice. Or at least the last elderberry jam I had was quite lovely. So that certainly makes for a confusing insult.
  
  They made booze from elderberries. The insult translates to "Your mother is a whore and your father is a drunk"
- Non native here: I even saw the movie.

In Australia, “40¢ short of a shout” is unlikely to be understood by visitors.
- Even as an Aussie I haven't heard that one.
- Non native didn't get it... Sounds like a reference of a specific event.
  
  Means they're 2 bob short of a dollar
- In Scotland it's "A couple of pieces short of a picnic", a piece being a sandwich
  
  Like his brain is not complete or something didn't get it not sure.
- Is it like a taco short of a combo plate?

In Australia, being a total bastard is a good thing, while being a bit of a bastard isn’t so good.
Mad cunt = good. Shit cunt = bad, see image
- Wow, I'm a native speaker and this confuses me.

"Bless (his/her/their/your) heart"
- That's not an insult as the internet has decided. It can be used sarcastically, but in my experience as a southerner it is more often a compliment for doing something nice.
  
  You had a different childhood than mine. It was code for "they're a moron".
  
  It’s used both ways, it’s just context dependent.
  
  South Louisiana here. It can be used affectionately (seeing a sick child and saying Bless your heart) but I find it is more often used to point out someone's lack of intelligence or bad behaviour (Karen is pitching an absolute fit in the checkout lane at Albertsons because she misread a price label...Bless her heart)
  Maybe you're from a more polite area of the south, but where I am we are heavily into calling out morons.
  
  Same here. “Bless your heart” usually means thank you

There are some southern or appalachian insults that I'm sure would confuse foreigners, even those who are functional in English.
Comparisons like "He's twelve ounces short of a pint", backhanded compliments like "I just love how you don’t care what people think", idioms like "three sheets to the wind". And then of course there's "rode hard and put up wet".
- There's also "bless your heart". Around here if someone tells you that, it is not a compliment.
  
  And each modifier between "your" and "heart" increases the factor of how insulting they're trying to be by at least 2
- Non native here: “three sheets to the wind” “rode hard and put up wet” are totally unknown and over my head.
  “He’s twelve ounces short of a pint” and “I just love how you don’t care what people think” I got them.
  
  Rode hard and put up wet is a reference to horses. Riding a horse hard and then not taking care of them after the ride can cause them issue, physically and mentally. It is usually used to say someone is tired or generally not well. Others, my mother included, use it to mean she thinks a woman has had too much wild sex, usually with too many partners.
  Three sheets to the wind, means to be drunk. It is from nautical terms meaning the sails are not fastened.

He’s got a couple of roos loose in the top paddock
- May your chickens turn to emus and kick your dunny door down
  
  Non native here: didn't heard that one before but I guess is wishing the person misfortune?
- Non native here: it's a variation of "he got some screws loose" we even use it a version of it in spanish.

"You make a better door than a window."

"He don't know shit from shinola." [I've never asked what "shinola" is.] EDIT: Another one my Dad uses (Oklahoma born and bred): calling someone a "mudcat".
- I’ve never asked what “shinola” is
  Let me clarify that for you.
  
  Here is an alternative Piped link(s):
  Let me clarify that for you.
  Piped is a privacy-respecting open-source alternative frontend to YouTube.
  I'm open-source; check me out at GitHub.
- Shinola is shoe grease
  
  Ah. Thank you.

Calling someone a Muppet. In NZ (and to a lesser degree, UK/Australia), it's a common thing to call someone who's being an idiot. Not sure why. I think as a nation we generally like the Muppets, but not someone who's being a Muppet.
- I think the connotation is that a Muppet is controlled by someone else. Their every thought, word, and action is the intent of their handlers.
  
  I think it's more that most Muppets are silly and not very intelligent
  
  That's a puppet. A muppet is someone being stupid

Does your face hurt? Because my eyes hurt.
- Non-native. I got this one.

You're being a wet blanket.
- Non native here: never heard it, is implying an unpleasant feeling?
  
  Usually it's referring to being a downer at an event that's typically exciting. Like being at a party but complaining the whole time about their beer/music selection.
  
  I have no idea how it started being used that way, but it's true, there's nothing fun about a wet blanket.

Fucktard

"Crayon eater", this one is specific to members of the U.S. Marine Corps, it can be used affectionately, but it's very context dependent.
- I like this one

Calling someone a Charlie.
https://greensdictofslang.com/entry/s7pwoia
- Non native here: (without going to the link) here in South America we sometimes call a person by "Juanito" or "Fulano" they are some sort of "Jhon Doe" names and the insult being "you're so irrelevant to me that I don't want to learn your name" or "who is this random person that came uninvited" is not common but some people still use it from time to time. Is akin of calling someone "furniture" (yeah that used as an insult in Argentina mostly). (going to the link) it make even less sense now....

Ya fucken mong

He’d be a great snipe hunter.

Suck my dick
- Here is an alternative Piped link(s):
  Suck my dick
  Piped is a privacy-respecting open-source alternative frontend to YouTube.
  I'm open-source; check me out at GitHub.
- This one make me rethink how I insult people really.
- That man is onto something. God bless!

Shitist? Either that or "You have a February nose, so full of frost, of storm and cloudiness."
- Non native here: "Shitist" Shit elitist? shithead? defecation goutmette?
  “You have a February nose, so full of frost, of storm and cloudiness.” Boogers?
  
  The Shitist thing is Australian I believe. I'm pretty sure it's just "shittiest" or just now looking at urban dictionary "the most shit anything can be".
  As for the other, I just looked up Shakespeare insults haha. Apparently it's "Your face looks cold and unpleasant, and you seem angry." According to the page I found it.

None because i'm not racist.
- jesse wtf are you talking about
  
  Don't side with the racists on this one, you're better than that.
- Bless your heart
- Language != Race
- What?
  
  We do need a word for these kinda comments. People who are so dull, boring and insignificant that they spend their entire time online attempting to be offended at literally fucking everything and everyone
- This person volunteered to be the one we can practice using this new knowledge on, bless their pure heart