have some fun with words! - umfahren
is a funny thing about the German word "umfahren".
It is just a joke, pls do not be encouraged. You do not spell them the same way: The thing, which knocks you down, is spelled as UMfahren, the thing, which goes around is pronounced umFAHREN. And it is an abbreviation (oh yes, the bad news, a valid one): The thing, which goes around is for HERUM-fahren. 'herum' is something like circle around. Shortened to "um", and then yes, if you read it, then in very, very rare cases, you do not know if it is - or the opposite.
You know what? Say "niederstoßen" instead. It is more common.
When you use "niederstossen" in the sense of "umfahren" you have to add "mit dem Auto" or any other vehicle. "Umfahren" always implies the use of a vehicle.
"Herumfahren" means to drive around aimlessly.
I would prefer "niederstoßen" before "umfahren" in doubt. The differences are more felt, than grammer. I rather would prefer niederstoßen for a person and umfahren for a thing. E.g. "Mister Minit wurde gestern früh von einem PKW niedergestoßen." or "Der alte Mann hat das Verkehrsschild einfach umgefahren!" but you can say as well (although I would not prefer): Mister Minit wurde von einem PKW umgefahren. and Der alte Mann hat ein Schild niedergefahren (hier vielleicht 'überfahren') It is a question of feeling and personal style.
And yes, "herumfahren" means to drive around aimlessly. But as well, it means 'um etwas herumfahren'.
E.g.: Der alte Mann ist um das Verkehrschild herum gefahren. Diesen Verkehrsstau wollen wir umfahren!
herumfahren means a lot of things: https://www.duden.de/rechtschreibung/herumfahren
No, this is not because German is hard. English words mean a lot of things as well. It took me decades of learning both languages (today I cannot speak neither of them any more, forgot my German and did not make it in English) to find out, that something like a matching translation of vocabulaies does not exist.
Gutes Gelingen! Cherrie
I disagree. You would never say "Er wurde von einem PKW niedergestoßen". Niederstoßen always requires a person, not a thing like a car, to do it.
I'm always puzzled about all the things we never think about when it comes to our own language. Thanks a lot for the input.
If I may add some aspects/corrections:
The spelling is exactly the same, just the accentuation is different.
Also I wouldn't agree, that umFAHren is an abbreviation. You say "etwas umFAHren" or "um etwas heRUMfahren".
Last but not least: niederstoßen is slightly different than UMfahren. The latter one involves "fahren" so you need to drive a car or ride a bike.
Ich umfahre das Hindernis. (I drive around the obstacle.)
Ich fahre das Hindernis um. (I run the obstacle over.)
exactly. Or: Ich fahre um das HIndernis herum (I drive around it)
Do not worry "herum" means alway 'around'.
Niederstoßen is really uncommon, it sounds very formal. Umfahren in this sense is very colloquial instead. A bit more common and formal is niederfahren.
Also possible. Sounds more like you accidentally hit a vase. Like umwerfen, but slightly more formal.
wouldn't use it. Umstossen means to topple something, not to run over it.
Just mentioned it, because it is the forth possible combination of nieder/um with stoßen/fahren
about: "niederstoßen" formal / common: I agree with formal, but not with uncommon. I expect it to read it in newspapers, accident reports or legal textes. I never wish anybody to be involved in an accident with persons insured in a German speaking country. But if he is, he shall understand the police protocol.