das Arschloch
asshole
A vulgar and strong insult for a person perceived as mean, inconsiderate, or unfair.
Er hat mich einfach angelogen, so ein Arschloch!
He just lied to me, what an asshole!

asshole
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asshole
A vulgar and strong insult for a person perceived as mean, inconsiderate, or unfair.
Er hat mich einfach angelogen, so ein Arschloch!
He just lied to me, what an asshole!

The word is a direct compound of 'Arsch' (vulgar for butt) and 'Loch' (hole). This literal meaning is the basis for its use as a strong insult.
Pass auf, wo du hintrittst, da ist ein tiefes Loch!
Watch where you step; there's a deep hole there!
Whether the insult or the anatomical meaning is intended becomes clear from context. If people are talking about someone's behavior, it is the insult. If people are talking vulgarly about the body, it means the anus.
Er hat sich allen gegenüber wie ein Arschloch verhalten.
He behaved like an asshole toward everyone.
This is a very vulgar and highly offensive swear word. It should only be used with great caution and in an appropriate informal context, because it is perceived as very hurtful.
Nenn mich nicht so, das ist eine Beleidigung!
Don't call me that; that's an insult!
As an insult, the word can directly describe a person ('Er ist ein Arschloch' — he is an asshole) or be used as an exclamation of outrage ('So ein Arschloch!' — what an asshole!).
Er ist wirklich ein Arschloch, er hat mich nie zurückgerufen.
He really is an asshole; he never called me back.
ass / asshole
'der Arsch' and 'das Arschloch' are both very vulgar words and can be used as crude insults. As insults, they are similar, but 'Arschloch' often sounds stronger and more directly aimed at a person. For the body, the difference is important: 'Arsch' means the buttocks, while 'Arschloch' means the anus. Learners may confuse the words because both are vulgar and both have to do with the body part. In polite situations, you should avoid both words.

Nach dem Streit nannte Tom den anderen ein Arschloch.
After the argument, Tom called the other person an asshole.
Nach dem langen Radfahren tat ihm der Arsch weh.
After the long bike ride, his ass hurt.