Es un sentimiento extraño.

Because ser is commonly used to identify or describe what something is in a more general sense.

• Es un sentimiento extraño = It is a strange feeling
• Está usually refers to a temporary state, condition, or location.

In this sentence, Spanish treats un sentimiento extraño as a thing being identified or classified, so es sounds natural.

That said, learners should know that Spanish sometimes uses está with adjectives in other contexts, but here es is the normal choice.

Spanish often leaves out the subject when it is understood from the verb.

• Es already means it is / he is / she is / you are depending on context.
• In this sentence, English needs it, but Spanish does not.

So Es un sentimiento extraño is a complete sentence even without a separate word for it.

Because sentimiento is a masculine noun.

In Spanish, articles must match the noun’s gender:

• un = masculine singular
• una = feminine singular

So:

• un sentimiento
• not una sentimiento

Even though the thing itself is not biologically male, nouns in Spanish still have grammatical gender.

A very common pattern is that nouns ending in -o are masculine.

So sentimiento follows that typical pattern.

Because it is masculine, the words around it must agree:

• un sentimiento
• extraño

If the noun were feminine, those forms would change.

Yes, you can say un extraño sentimiento, but the meaning or emphasis can shift slightly.

In Spanish, adjectives often come after the noun:

• un sentimiento extraño = a strange feeling

If you put the adjective before the noun, it can sound more literary, expressive, or stylistically marked:

• un extraño sentimiento

For a learner, un sentimiento extraño is the most neutral and straightforward version.

Because the adjective must agree with sentimiento, which is masculine singular.

So:

• sentimiento → masculine singular
• adjective must match → extraño

Compare:

• un sentimiento extraño
• una sensación extraña

The adjective changes to match the noun, not the real-world thing being described.

No. Extraño can have more than one meaning depending on context.

As an adjective, it can mean:

• strange
• odd
• unusual

But extraño can also be a verb form from extrañar:

• Te extraño = I miss you (common in Latin America)

In Es un sentimiento extraño, it is clearly an adjective meaning strange.

A good approximate pronunciation is:

es oon sen-tee-MYEN-to eks-TRAH-nyo

A few key points:

• ñ is pronounced like ny in canyon
• j does not appear here, so there is no harsh throat sound
• the stress in sentimiento falls on mien
• the stress in extraño falls on tra

So extraño sounds roughly like eks-TRAH-nyo.

Both can sometimes translate as feeling, but they are not always identical.

• sentimiento often refers more to an emotion or inner feeling
• sensación often refers more to a sensation or physical/immediate impression

So:

• Es un sentimiento extraño suggests an emotional or inner feeling
• Es una sensación extraña can sound more like a sensation, impression, or bodily feeling

In real life, there can be overlap, but this is a useful distinction.

No, that would not sound natural here.

You need the indefinite article:

• Es un sentimiento extraño

Without un, the sentence is incomplete or ungrammatical in normal Spanish.

Spanish uses articles quite often, sometimes more often than English learners expect.

Yes, you could, but the nuance is a bit different.

• extraño = strange, unusual, odd
• raro = strange, weird, unusual

In many contexts they overlap. However:

• extraño can sound a little more neutral or descriptive
• raro can sometimes sound more like weird

So Es un sentimiento extraño may sound slightly more natural if you want strange without sounding too strong or informal.

It is neutral. It is neither especially formal nor especially informal.

You could use it in everyday speech, writing, conversation, or narration. Nothing in the sentence is slangy or overly formal.

Grammatically, es could refer to different subjects depending on context, but in this sentence the phrase un sentimiento extraño makes it clear that we are talking about it as an idea, situation, or experience.

So while es can mean:

• he is
• she is
• it is
• you are (formal singular)

here the natural interpretation is it is.

It can be singular or plural depending on what you want to say.

• Es un sentimiento extraño = It is a strange feeling
• Son sentimientos extraños = They are strange feelings

In your sentence, the idea is singular: one feeling.

If you make the noun plural, the article, adjective, and verb all need to match:

• unos sentimientos extraños
• son sentimientos extraños