Different cultures have different colloquialisms and it can be fun and interesting to see where their most common insults and teases come from. It is also good to recognize these in case you accidentally upset someone and they happen to say one of these to you...
meaning "twit" or idiot
Literally: as cowardly as a goat
Meaning: bloody coward
Fjandi/ Djöfull/Andskoti/sá í neðra/
translates to the devil. This word is used in most of the Scandinavian languages I prefer Andskotans as it means more like "by the devil!
This one is my personal favorite. It is used the same way that in English you would call someone a scumbag. However, it literally translates to "poop on two legs" or "poop walking".
This is a loan word from English. Guess what it means
this is the Icelandic equivalent to "shut up" so it is quite a rude way to tell someone to be quiet!
This one is equivalent with dirt bag
farðu til fjandans
Go to the devil
A person that is so awful they can be compared to bad breath.
Farðu til helvítis
(Fahr-Thoo Tiihl Hehlveetihs)
Go to hell
Extra awesome swearword: Helvítis fokking fokk
Hopefully you can add the above to your cursing repertoire! It is a good way to curse at work too, since people won't know what it means ;)