Learn Hardcore German: Wir dürfen die Frist nicht versäumen.

It expresses prohibition: “must not” / “are not allowed to.” In English, “may not” can sound like “it’s possible that not,” but German dürfen nicht never means that. It’s always about permission being denied.

Why is nicht placed before versäumen? Could I say Wir dürfen nicht die Frist versäumen?

Standard word order is: subject + finite verb + objects/adverbials + nicht + non‑finite verb(s). So Wir dürfen die Frist nicht versäumen is the neutral, correct order.
Wir dürfen nicht die Frist versäumen is only used for contrastive emphasis (“not the deadline [but maybe something else]”), and sounds odd unless you’re contrasting explicitly.

What case and gender is die Frist, and why die?

Frist is feminine (die Frist). Here it’s the direct object of versäumen, so it’s in the accusative singular—which for feminine nouns is also die. Indefinite would be eine Frist; plural: Fristen.

What’s the difference between versäumen and verpassen?

Both can mean “to miss,” but:

versäumen is a bit more formal and often used with obligations/opportunities: eine Frist/Chance versäumen.
verpassen is very common in speech and with transport/events: den Zug/Termin verpassen.
With deadlines, both work, but die Frist versäumen is a strong collocation.

Is versäumen a separable verb? How do I form the past?

No. Prefix ver- is inseparable.

Simple past: ich versäumte
Perfekt: ich habe … versäumt (e.g., Wir haben die Frist versäumt.)

How would this look in a subordinate clause?

Both verbs go to the end as an infinitive cluster, with the lexical verb before the modal:
…, weil wir die Frist nicht versäumen dürfen.
This is the normal order in subordinate clauses.

Can I say it in a more positive way?

Yes: Wir müssen die Frist einhalten. (We must meet the deadline.)
Compare: prohibition (dürfen … nicht) vs obligation (müssen … in a positive formulation).

Are Frist and Termin the same?

No.

Frist = a time limit/deadline by which something must be done (often legal/administrative).
Termin = an appointment/meeting/date/time slot.
So den Termin verpassen = miss the appointment; die Frist versäumen = miss the deadline.

Pronunciation tips for key words?

dürfen: Ü = rounded “ee” (say “ee” while rounding lips): roughly “DÜR-fen” [ˈdʏʁfən].
Frist: short i, final -st: [fʁɪst].
versäumen: v like English “f”; äu sounds like English “oy”: “fer-ZOY-men” [fɛʁˈzɔʏmən].
In Wir, the r is not fully rolled; think quick “veer.”

When would I use kein instead of nicht here?

Use kein to negate an indefinite noun:

General statement: Wir dürfen keine Fristen versäumen. (no deadlines, in general)
Specific known deadline: Wir dürfen die Frist nicht versäumen.

Is Wir dürfen die Frist nicht verpassen also correct?

Yes. It’s perfectly fine and more colloquial. With deadlines, versäumen feels a bit more formal; verpassen is very common in everyday speech.

How can I make this a general rule (“one/you must not…”)? What about an imperative?

General: Man darf die Frist nicht versäumen.
Instructional “you”: Du darfst die Frist nicht versäumen.
Imperative (warning): Versäumt die Frist nicht! / Versäumen Sie die Frist nicht!

Where does a pronoun go? For example, if I replace die Frist with sie?

Pronoun objects stay before nicht:
Wir dürfen sie nicht versäumen. (Here sie = feminine accusative singular, referring to die Frist.)

Does müssen nicht mean “must not”?

No. müssen nicht means “don’t have to” (lack of necessity), not prohibition.

Prohibition: Wir dürfen die Frist nicht versäumen. (must not)
Lack of necessity: Wir müssen die Frist nicht versäumen. (It’s not necessary for us to miss the deadline—odd sentence.)
Use dürfen … nicht for “must not.”