Feche o olho.

Feche is the affirmative command form of fechar for você in Brazilian Portuguese.

A useful way to think about it:

• infinitive: fechar = to close
• present subjunctive: que você feche
• command to você: feche!

So Feche o olho. is built like a command directed at you.

Because standard Brazilian Portuguese forms commands differently depending on which you is being used.

For você, the command uses the same form as the present subjunctive:

• feche = close! / close it!

For tu, the command is usually:

• fecha in many spoken varieties
• or more formally/grammatically traditional: fecha as the affirmative imperative from tu

In most of Brazil, você is very common, so feche sounds like a normal command to you.

Portuguese often uses the definite article with body parts where English uses a possessive.

So instead of saying:

• your eye

Portuguese often says:

• the eye = o olho

This is very common with body parts and clothing, especially when it is already obvious whose body part is meant.

Examples:

• Lave as mãos. = Wash your hands.
• Abra a boca. = Open your mouth.
• Feche os olhos. = Close your eyes.

Using seu olho is possible in some contexts, but here it is less natural unless you really want to emphasize possession.

Yes—if you mean both eyes, the most natural sentence is usually:

• Feche os olhos.

The singular Feche o olho. usually suggests one of these ideas:

• close one eye
• close that eye
• a specific eye is being referred to
• a slightly colloquial or context-dependent instruction

So a learner should know:

• Feche o olho. = close the eye / close one eye
• Feche os olhos. = close your eyes

In many everyday situations, os olhos is the version you will hear more often.

Yes, the subject is omitted because Portuguese often leaves it out when it is clear from the verb form or the context.

In Feche o olho., the implied subject is:

• você

So the full idea is:

• Você, feche o olho.

But saying você is usually unnecessary unless you want emphasis, contrast, or clarity.

It is usually neutral to polite, because it uses the você command form feche.

In Brazilian Portuguese, você is extremely common and does not automatically sound very formal. Depending on tone and context, feche can sound like:

• a normal instruction
• a polite command
• something a doctor, teacher, or parent might say

A more colloquial spoken version in some regions might be:

• Fecha o olho.

But Feche o olho. is a good standard form to learn.

In many situations, yes.

If you are telling someone to close both eyes, Feche os olhos is the most natural choice.

Use Feche o olho when:

• you really mean just one eye
• the context makes one eye specific
• someone is winking, aiming, or being examined

So the difference is mainly about number and context, not grammar.

Olho is pronounced roughly like OH-lyoo, but the lh sound is important.

A few pronunciation notes:

• o = usually like oh
• lh = a palatal sound, similar to the lli in million for many English speakers
• final o in Brazilian Portuguese often sounds closer to oo

So olho is approximately:

• OH-lyoo

Not like English log or low.

And Feche o olho flows together in speech, often sounding something like:

• FEH-shee u OH-lyoo

Exact pronunciation varies by region.

Yes, and that can be more explicit if you mean one eye.

Compare:

• Feche o olho. = Close the eye / close your eye.
• Feche um olho. = Close one eye.

If you want to make the idea of one very clear, um is useful. Without um, the sentence may rely more on context.

Not by itself. Commands in Portuguese are not automatically rude.

Whether Feche o olho. sounds rude depends on:

• tone of voice
• situation
• relationship between speakers

For example, it could sound perfectly normal in these contexts:

• a doctor giving instructions
• a photographer directing someone
• a parent helping a child
• a game or joke

If you want to sound softer, you can add polite language, such as:

• Por favor, feche o olho.

That makes it clearly more polite.

Yes, very naturally.

Feche o olho. fits situations where one eye matters specifically, for example:

• an eye exam
• putting in eye drops
• checking irritation
• asking someone to protect one eye
• giving instructions for makeup or cleaning around the eye

That is one reason the singular can sound completely natural in context.