"Sperren" means "lock". "Aufsperren" means "unlock". The "auf" here means to negate or "open" or something?

Sorry, I am not sure if this is an appropriate question to ask. Because the answer could simply be that, "auf" means nothing and "aufsperren" just means "unlock". You could say that it is just what it is and there is no need to ask what "auf" here means.

But for me I want to ask because if I know what "auf" means, and it will be easier for me to remember both meanings of "sperren" and "aufsperren". Otherwise I might confuse the two. And maybe there are other verb pairs similar to "sperren" and "aufsperren".

  • Just wanted to note that the more used translation (I think? please correct me if I'm wrong) of "unlock" is "entsperren", at least in the meaning of unlocking a phone by typing in the password. As the answers have already explained, "Aufsperren" has more to do with opening things physically.
    – kscherrer
    Nov 8, 2018 at 10:37
  • The confusion is probably because "auf-" also means "up". But then, in english, buildings eventually burn up when they burn down, people get locked up when they get locked down..... Nov 8, 2018 at 20:28

2 Answers 2


Many German separable verb prefixes have somewhat obscure or arbitrary meanings, but auf- is actually fairly consistent. It means "opening" in verbs such as aufschliessen, aufmachen, aufsperren, aufschrauben etc.

There are also other consistent meanings in other fields; aufschliessen, aufholen, aufkommen all mean to decrease someone else's lead in a race, and aufrichten, aufstehen, aufspringen etc. all mean to become upright. You'll note that several of these meanings are subtly connected:for instance, it is intuitively much more likely to associate gaining on someone with the up direction than the down direction. Much-used particles almost always live in a web of interconnected meanings like this.

  • 1
    Note that aufmachen has multiple meanings and may fall in several of these categories: In einen Brief aufmachen = to open a letter we have auf = open. On the other hand, the reflexive sich aufmachen = to start walking/moving/leaving is related to auf = up (as in to stand UP and leave). Not to mention the phrase sich auf den Weg machen (which also means to start leaving) where auf belongs to Weg instead of machen (literally, to make oneself onto the road) Nov 8, 2018 at 9:49
  • Well, some other forms with that prefix are more confusing. E.g. "aufwaschen" is used sometimes, while I prefer "abwaschen". That word "aufwaschen" has nothing to do with "opening".
    – harper
    Nov 9, 2018 at 5:59

As pointed out in Kilian's answer, the "auf" prefix here refers to opening something.

It does, however, not negate the pre-ixed word in general (e.g. as opposed to how "to lock"/"to unlock" work in English). Rather than that, the pair with explicit prefixes in German is "zusperren"/"aufsperren".

In there, "auf" has the aforementioned meaning of opening something, as it also appears in

  • aufschließen
  • aufklappen
  • aufmachen (= öffnen)

and "zu" has the meaning of closing something, consistently with words such as

  • zuschließen
  • zuklappen
  • zumachen (= schließen)

With that in mind, "sperren" can be considered a shorter form of "zusperren", as some kind of a default action done with respect to the concept of "sperren".

Among the above verb pairs, only "aufschließen"/"zuschließen" can be used in such a way that the unprefixed verb "schließen" can have the same meaning as "zuschließen", so this is not a general trait of all such pairs.

  • @IQV: Thank you, fixed. The joys of typing on a mobile. Nov 8, 2018 at 8:42
  • "sperren" is "to block something". "Die Straße sperren" - To block the road.
    – Trish
    Nov 8, 2018 at 11:34
  • @Trish: True, "sperren" without a prefix has quite some more meanings beyond locking something in some way, all related more generally to preventing some movement. Nov 8, 2018 at 11:36
  • 2
    "Auf" and "Zu" are common words for referring to "open" and "closed" - "Mach die tür zu!" or "Hat der Laden auf?" - "Nein, der Laden ist zu."
    – Falco
    Nov 8, 2018 at 13:22
  • @Falco: Well, "Mach die Tür zu!" is simply an example of "zumachen" in a sentence. Nov 8, 2018 at 13:30

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