Hier means a place where the speaker currently is. Her means a direction towards the speaker. Hierher means to follow the direction until you reach the speaker. For the above sentence, you could also just say "Kommen Sie nicht her".
bruh german grammar is so specific, it's awesome but as the same time frustrating.
From what you're saying, it sounds like all there forms of "here" would work in this sentence without context.
So, if I get it right, if you walk in the opposite direction from the speaker it would be hierHIN?
It would probably be "DAhin", because "hier" is still near the speaker. You would probably only use "hierhin" if you stand right next to a dog turd and don't want the other person to step on it ("Treten Sie nicht hierhin!"). You would use "hierHER" in a similar situation, if you already stand in the problematic environment yourself.
Is "hither" used frequently? I've never heard it before. English is not my native language.
No, hither is not used very often. English used to have all kinds of "where..." and "there..." words like German's "wo..." and "da..." words, but they've mostly died out. Hither (to here), thither (to there), whither (where to), hence (from here), thence (from there), whence (where from), therefore (because of that), wherefore (why), etc. Hence and therefore still exist, but hence is now almost exclusively used to mean "thus."
Old English is the answer to hierher vs hier
Kommen Sie nicht hierher. = Do not come hither.
Woher kommst du? = Whence do you come?
Wohin gehst du? = Whither are you going?
I wrote the same thing... as in, in a general way they do not go towards the wherever that person is.
That would be "Sie kommen nicht hierher." The word order is different in both the German and English sentences.
Why "They don't come here" is wrong? I understand that here Duolingo proposes the imperative form but present tense should work; shouldn't it?
For a statement sentence, you would need a different word order. The verb would be in second place:
Sie kommen nicht hierher = they don't come here
I believe 'hier' is synonym to 'hierher', otherwise the speaker would not say 'hier' or 'hierher' but 'da' or 'dort' ?
No, "hierher" is a direction (=towards here), while "hier" is a location (=right here).
If it is in the imperative form, shouldn't it have an exclamation point at the sentence end?
How can people say German is easy; English doesn't have 100 words for the same thing or different "the" and "a"'s. The only thing hard is learning of different pronunciations... It's annoying having to learn a word, then learn on down the line meaning the exact same thing.. but not the same .. .
In my opinion, it's a relatively logical language with straightforward, more universal rules, among the European languages. Compare to French, where there are three ways a verb can be conjugated, and the verbs don't have any conceivable difference in functionality. In German all (most?) verbs and adjectives are conjugated via one method, excluding modal verbs, which have different functionality to common verbs.
To me, French is to German as German is to English. I don't know much French at all though, so I cannot really say for sure, but I know the other major romance languages are easier.
And English also has words that change in conjuncted words.