pasuwaadokanriapuri de pasuwaado no tukaimawsi wo sakeru.

It is a compound noun made of three parts:

• パスワード = password
• 管理 = management
• アプリ = app

So パスワード管理アプリ means a password management app or more naturally a password manager app.

Japanese often stacks nouns together like this without extra words such as for, of, or that manages.

Here, で shows the means/tool/method used to do something.

So:

• パスワード管理アプリで = with a password manager app / by using a password manager app

It tells you how the action is carried out.

Compare:

• 箸で食べる = eat with chopsticks
• アプリで管理する = manage something with an app

In this sentence, the idea is that the app is the tool used to help avoid password reuse.

使い回し means using something again and again in different places, often in a way that is not ideal.

In this sentence, パスワードの使い回し means reusing the same password across multiple accounts or services.

It comes from the verb 使い回す, which means to use repeatedly or to reuse in multiple contexts.

So this is not just use again once. It has the nuance of recycling the same thing over and over.

The の links パスワード to 使い回し.

So:

• パスワードの使い回し = the reuse of passwords / password reuse

You can think of it as similar to of in English, though Japanese の is broader than English of.

It turns パスワード into the thing being reused.

を marks the direct object of the verb.

Here:

• パスワードの使い回し = the thing being avoided
• を避ける = avoid it

So:

• パスワードの使い回しを避ける = avoid reusing passwords

This is a very standard pattern:

• 危険を避ける = avoid danger
• トラブルを避ける = avoid trouble

避ける means to avoid.

In this sentence, it means avoiding the practice of password reuse.

A few common uses:

• 危険を避ける = avoid danger
• 人混みを避ける = avoid crowds
• 使い回しを避ける = avoid reusing something

So the sentence is describing a recommended action: use a password manager app to avoid reusing passwords.

Yes. Japanese often omits the subject when it is understood from context.

This sentence could imply:

• You should avoid password reuse with a password manager app
• Use a password manager app to avoid reusing passwords
• Avoid password reuse by using a password manager app

Which one is best depends on the surrounding context. In Japanese, leaving out the subject is extremely common.

The dictionary form is often used in:

• headings
• instructions
• slogans
• general statements
• bullet-point advice

So this sentence sounds like something you might see in:

• an app guide
• a security checklist
• a website tip
• a heading in an article

If you made it more polite and sentence-like, you could say:

• パスワード管理アプリで、パスワードの使い回しを避けましょう。 = Let’s avoid reusing passwords with a password manager app.

No. Normal Japanese would usually be written without those spaces:

• パスワード管理アプリでパスワードの使い回しを避ける。

The spaces were probably added just to help learners see the parts more clearly.

Yes, but the nuance may change.

For example:

• 再利用 = reuse, reutilization
• 使い回し = repeated reuse, often casually or in a not-so-good way

In the context of passwords, 使い回し is very common because it naturally expresses using the same password over and over for different services.

So it fits this cybersecurity context very well.

Here it means with / by using.

The particle で has several uses, so learners often get confused. It can mark:

• the place where an action happens
• the means by which something is done
• the material something is made from

In this sentence, it is the means/tool use:

• アプリで避ける = avoid it with an app / by using an app

So with is the best interpretation here.

A natural breakdown is:

• パスワード管理アプリで = using a password manager app
• パスワードの使い回しを = password reuse
• 避ける = avoid

So the structure is:

[tool/method] + [thing to avoid] + [verb]

That gives the overall sense:

• Use a password manager app to avoid reusing passwords
• Avoid password reuse with a password manager app

Both are good natural understandings.