La professeure ne veut punir personne, mais elle doit le faire si un élève copie sur sa voisine.

Professeure is a feminine form meaning female teacher / female professor. In modern French, many job titles now have feminine forms, and professeure is common.

That said, you may also hear le professeur or even la professeur in some contexts, depending on region, register, or personal preference. But la professeure is a perfectly normal modern choice for a woman.

Also, prof is a very common short form in everyday French.

In French, personne can mean nobody / no one when it is used in a negative structure.

So:

• ne ... pas = not
• ne ... personne = nobody / no one

Here, personne replaces pas. You do not say ne veut pas punir personne in standard French if you mean wants to punish nobody, because that would create a double negative in a way French does not use here.

So:

• Elle ne veut punir personne = She does not want to punish anyone / She wants to punish nobody.

Because personne is the object of the infinitive punir.

The structure is:

• elle ne veut = she does not want
• punir personne = to punish nobody / to punish anyone

So the sentence is built around vouloir + infinitive:

• elle veut punir quelqu’un = she wants to punish someone
• elle ne veut punir personne = she does not want to punish anyone

In other words, personne belongs with punir, not directly with veut.

Because after vouloir (to want), French normally uses an infinitive.

Examples:

• Je veux partir. = I want to leave.
• Elle veut aider. = She wants to help.
• La professeure veut punir. = The teacher wants to punish.

So veut punir simply means wants to punish.

It means she must do it or she has to do it.

Here:

• doit comes from devoir = must / have to
• le faire = do it

The little word le stands for the action already mentioned, namely punir quelqu’un.

So instead of repeating:

• mais elle doit punir quelqu’un

  French uses:

• mais elle doit le faire = but she has to do it

This is very natural in French.

Because le can refer to an idea, action, or whole clause, not just a masculine noun.

Here it does not mean him. It means something like that or it, referring to the act of punishing.

So:

• le faire = to do it / that

Compare:

• Elle doit punir un élève.
• Elle doit le faire.

In English, we also often use do it instead of repeating the whole action.

Copier sur quelqu’un is a common French expression meaning to copy from someone, especially in the sense of cheating in class.

So:

• copier = to copy
• copier sur quelqu’un = to copy from someone’s work / cheat off someone

Even though sur usually means on, in this expression you should learn it as a set phrase:

• copier sur son voisin
• copier sur sa voisine

Both mean to copy from the person next to you.

Here, sa voisine means his/her female neighbor or, more naturally in a classroom context, the girl sitting next to him/her.

The noun voisine is feminine, so the possessive is sa.

Important point: in French, sa agrees with the thing possessed, not with the owner.

So:

• son voisin = his/her male neighbor
• sa voisine = his/her female neighbor

This does not tell you whether the student is male or female. It only tells you the neighbor being copied from is female.

Not necessarily.

Élève can refer to a student of either sex. The article un is masculine grammatical gender, but in many contexts French uses the masculine form when the gender is unknown, unspecified, or meant generically.

So un élève here can mean:

• a male student
• or simply a student in general

If French wanted to make it clearly feminine, it could say une élève.

Because after si meaning if, French normally uses the present tense when talking about a real future possibility.

So French says:

• si un élève copie... = if a student copies / if a student is copying

Even when English might say if a student copies, if a student does copy, or sometimes think in future terms, French still uses the present after si.

A useful rule is:

• si + present, then the result can be present, future, or imperative depending on meaning.

Here:

• si un élève copie sur sa voisine, elle doit le faire
• if a student copies from the girl next to them, she has to do it

Yes. Personne can mean either:

• person / people in some contexts
• or nobody / no one in a negative structure

Compare:

• Il y a une personne devant la porte. = There is a person in front of the door.
• Il n’y a personne devant la porte. = There is nobody in front of the door.

In your sentence, because of ne ... personne, it clearly means no one / anyone in a negative sense.

Because mais means but, and it connects two contrasting ideas:

• La professeure ne veut punir personne
• mais elle doit le faire...

The comma helps separate those two parts clearly, just as in English you would often write:

• The teacher does not want to punish anyone, but she has to...

So the punctuation is very natural and standard.

In everyday French, voisin / voisine can mean not only a literal neighbor, but also the person next to you.

In a classroom sentence like this, sa voisine is best understood as:

• the girl next to him/her
• the female classmate sitting beside him/her

So although the basic meaning of voisine is female neighbor, the classroom meaning is broader and very natural.