What is the difference between "nicht gerade," "nicht ganz," "nicht genau," "nicht wirklich," and "nicht unbedingt"?

Question

An expression I often use (especially when trying to explain something to someone in a language other than my mother tongue) is:

Not exactly.

The conversation usually goes something like this:

Are you saying ___________ ___________ ___________?
Not exactly.

I am, at best, at the A2 level in German (and some days I feel more like an A0). Consequently, I rely a lot on machine translators to get me through a conversation. I was doing just this, just this morning, when I wanted to say "Not exactly." The machine translator (DeepL), gave me this:

nicht gerade

Sometimes, while I am looking something up with a machine translator, I'll ask

Wie sagt man auf Deutsch ...

just to buy me a little time. Such was the case with my inquiry into "Not exactly." My interlocutor this time was an iTalki tutor of German who, if I'm not mistaken, lived in Germany for something like six years. I pose this question here not because I doubt his mastery of German. I find his pronunciation flawless and he seems quite fluent. I pose this question because our exchange over this one phrase leaves me a bit confused. If my memory serves me correctly, it went something like this:

Wie sagt man auf Deutsch "not exactly"?
Nicht unbedingt.
[AFTER LOOKING AT THE DEEPL TRANSLATION] I can't say "nicht gerade"?
Nein.
"Nicht unbedingt" ist besser?
Ja.

My next question should have been "Warum?" but instead my mind just attempted to process all of this and, such as is the case with most conversations, they are so fluid and fast that you really don't have time to investigate all the myriad of mysteries a language may present in even the shortest of conversations. Later, I decided to look into it a bit more deeply (which is when I discovered that "nicht ganz," "nicht genau," and "nicht wirklich" are other options/synonyms for "not exactly").

By "a bit more deeply" I mean I visited Reverso and conducted a Google search. This usually leads me to an answer that satisfies me to some degree, but this time it didn't. So, I decided to post my question here. What I want to know is, what is the difference between these five phrases (or any other similar ones) and when can I use which?

Answer 1

"Not exactly" can have different implications depending on context. .

Let's go through these possible translations:

1) "nicht gerade" / "nicht genau"

I agree with your tutor, I would never use "Nicht gerade." as a short phrase on its own, that's not idiomatic. "Nicht gerade" has its place in a sentence when you want to say that the thing you're describing is less that what you're comparing it to:

Das ist nicht gerade Zauberei. (That's not exactly rocket science)

This means that it is less than rocket science / magic.

Das Wetter war ja nicht gerade besonders gut. (The weather wasn't exactly great.)

"Nicht genau" is a similar case - it doesn't work as an answer on its own. The approving "Genau!" that Germans love to use can't be negated.

2) "Nicht unbedingt." (not necessarily)

This means that there are some conditions ("Bedingungen") where the explanation is wrong. The explanation is only "bedingt" correct, some conditions apply.

"Amerikanisches Bier ist schlecht." - "Nicht unbedingt. Viele große Biere sind schlecht, aber Microbreweries brauen sehr gutes Bier."
"American beer is bad" - "Not in every case. Many big beer brands are bad, but microbreweries brew some very good beer."

3) "Nicht ganz." (literally: not entirely, not completely)

I think this is the most similar to "not exactly" in your context. Literally, it means that the explanation is not wrong, but not totally right either. The whole sentence would be "Das ist nicht ganz richtig." ("That's not entirely/completely correct.").

As a euphemism, it can also be a way of saying that what the other person said is entirely incorrect.

"Einstein bewies, dass E = mc³." - "Nicht ganz. E = mc²."
"Einstein showed that E = mc³." - "Actually, E = mc²."

This works especially well when answering to a question like "Are you saying ...." / "Willst du damit sagen ..." / "Meinst du ...", as in your example:

"Meinst du damit, dass Energie und Masse dasselbe sind?" -- "Nicht ganz. Masse und Energie sind gleichwertig, man kann Masse in Energie umrechnen."

4) "Nicht wirklich." (not really)

has only become popular in recent decades, it's informal, and it's basically a 1:1 translation of the English idiom "not really". It can be quite strong as an objection and border to accusing the other of not knowing what they're talking about at all, or even lying.

"In China kann man sich mit Englisch gut verständigen." - "Nicht wirklich. Nur Chinesen, die viel mit Ausländern zu tun haben, lernen Englisch."
"In China, you can get by with English quite well." - "Not really. Only Chinese who are in contact with foreigners a lot learn English."

tl;dr: Don't use "Nicht gerade." and "Nicht genau.". Use "Nicht unbedingt." ("Not necessarily."), "Nicht ganz." ("I don't agree entirely.") or "Nicht wirklich." ("Not really.") depending on what you're criticizing and how strongly you're objecting.