Страх исчез.

Страх is in the nominative singular. In this sentence, it is the subject — the thing that disappeared.

• dictionary form: страх
• gender: masculine
• number: singular
• case: nominative

So this is the normal form you would expect for the subject of a sentence.

Исчез is a past tense form, while исчезает is present tense.

Here the sentence describes a completed event, so исчез is the natural choice.

Compare:

• Страх исчез. = the fear disappeared / has disappeared
• Страх исчезает. = the fear is disappearing

So исчез tells you the disappearance already happened.

Исчез comes from the infinitive исчезнуть, which means to disappear.

This is the masculine singular past tense form:

• исчез — masculine
• исчезла — feminine
• исчезло — neuter
• исчезли — plural

Because страх is a masculine singular noun, the verb appears as исчез.

That is a very reasonable question, because learners often see past tense forms like:

• делал
• сказал
• читал

But исчезнуть has the masculine past form исчез, not исчезл.

This is just the correct past-tense pattern for this verb. You can see the usual past-tense endings more clearly in the other forms:

• исчезла
• исчезло
• исчезли

So the important thing to remember is simply:

• infinitive: исчезнуть
• masculine past: исчез

Исчезнуть is perfective.

That means it presents the action as a completed whole: the fear went away, and that disappearance is viewed as finished.

Its imperfective partner is исчезать.

Compare:

• Страх исчез. — the fear disappeared
• Страх исчезал. — the fear was disappearing / used to disappear

In this sentence, the perfective verb fits because the result matters: the fear is gone.

Russian does not use articles like English the and a/an.

So страх can mean:

• fear
• the fear
• sometimes even a fear

The exact meaning depends on context.

In a short sentence like Страх исчез, English usually needs an article, but Russian does not.

Yes. Russian word order is much more flexible than English word order.

Both of these are grammatically possible:

• Страх исчез.
• Исчез страх.

The difference is mostly one of emphasis or style.

• Страх исчез. sounds neutral: fear disappeared
• Исчез страх. gives more emphasis to the fact that it disappeared

For a learner, Страх исчез is the easiest neutral pattern to understand.

No. Russian does not require a separate pronoun if the noun is already there.

Страх is the subject, so the sentence is complete:

• Страх исчез.

Adding он would usually be unnecessary here.

Russian often sounds more natural without an extra pronoun when the subject is already clearly stated.

Here the verb is intransitive, so it does not take a direct object.

You do not say that something disappeared something. Instead, the subject itself disappears:

• Страх исчез.
• Туман исчез.
• Боль исчезла.

So this sentence is complete exactly as it is.

A simple learner-friendly pronunciation is:

• страх ≈ strakh
• исчез ≈ is-CHEZ

Stress:

• стрАх
• исчЕз

A few useful notes:

• х sounds like the ch in Scottish loch or German Bach
• ч is like English ch
• the stress matters, especially in исчез

So the full sentence is approximately:

strakh is-CHEZ