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.

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

Your father smells of elderberries.

In Australia, “40¢ short of a shout” is unlikely to be understood by visitors.

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

"Bless (his/her/their/your) heart"

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".

He’s got a couple of roos loose in the top paddock

"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".

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.