चाकू पर नज़र रखिए।

A natural pronunciation is:

chaakū par nazar rakhiye

A few quick notes:

• चाकू = chaa-koo
  
  • चा has a long aa
  • कू has a long oo
• पर = par, but the vowel is usually a quick, neutral sound, closer to pər
• नज़र = nazar
  
  • with ज़, many speakers say a z sound
• रखिए = rakhiye
  
  • ख is an aspirated k sound: kh
  • the ending -इए / -iye gives it a polite command tone

So the whole sentence sounds roughly like:

chaa-koo pər na-zər ra-khi-ye

Yes. नज़र रखना is a very common Hindi expression.

Literally:

• नज़र = sight, gaze, eye
• रखना = to keep, to place

But together, नज़र रखना means:

• to keep an eye on
• to watch
• to keep track of
• to monitor

So in this sentence, Hindi is using a natural idiom, not just translating word-for-word from English.

Because the pattern in Hindi is:

X पर नज़र रखना = to keep an eye on X

So:

• चाकू = knife
• पर = on
• नज़र रखना = keep an eye

Literally, it is something like keep your gaze on the knife.

Even though English might say watch the knife or keep an eye on the knife, Hindi naturally uses पर with this expression.

रखिए is the polite imperative form of रखना.

Here is the basic idea:

• रखना = to keep / to place / to keep watch
• रखो = keep!
  
  • informal
• रखिए = please keep / keep
  
  • polite, respectful

So चाकू पर नज़र रखिए is a polite or respectful instruction.

You would use रखिए for:

• आप
• formal situations
• respectful speech
• polite instructions

Grammatically, it is an imperative, so it is a command form.

But in actual tone, रखिए often sounds like:

• a polite instruction
• a respectful request
• practical advice

So depending on context, it could feel like:

• Please keep an eye on the knife
• Watch the knife
• Make sure you keep track of the knife

It is not as blunt as an English bare command can sound.

Hindi does not have articles like English a/an and the.

So चाकू can mean:

• a knife
• the knife

The context tells you which one is meant.

In a real situation:

• if everyone knows which knife is being talked about, it will feel like the knife
• if it is not specific, it could feel like a knife

This is very normal in Hindi. Learners often want to find a word for the, but usually there just isn’t one.

Yes, in many situations they refer to the same word.

• नज़र uses ज़, which represents a z sound
• नजर is a simplified spelling often seen in everyday writing

Many speakers pronounce them very similarly, and in casual Hindi you will often see both spellings.

For a learner:

• नज़र is a careful spelling
• नजर is also very common in practice

Both are widely understood.

Yes, you can say चाकू को देखिए, but it does not mean exactly the same thing.

• चाकू को देखिए = Look at the knife
• चाकू पर nज़र रखिए = Keep an eye on the knife / Watch the knife

The difference is:

• देखिए suggests simply looking
• नज़र रखिए suggests continuing attention, monitoring, or being careful about it

So if the idea is watch it carefully or make sure it stays in sight, then नज़र रखिए is the better choice.

The dictionary form is रखना.

That is the infinitive, meaning:

• to keep
• to place
• to put
• in some expressions, to maintain or to keep watch

In this sentence:

• base verb: रखना
• polite command form: रखिए

So when you look this up, you should look for रखना, not रखिए.

This order is the most natural and standard for this sentence.

The structure is:

[thing being watched] + पर + नज़र + रखिए

So:

• चाकू पर = on the knife
• नज़र = eye / attention
• रखिए = keep

Hindi word order can sometimes shift for emphasis, but चाकू पर नज़र रखिए is the default, natural phrasing.

If you changed the order, it might still be understood, but it could sound marked or less natural.

It is polite-neutral.

Because of रखिए, it sounds:

• respectful
• appropriate in many normal situations
• not rude
• not extremely formal either

Compare:

• चाकू पर नज़र रखो।
  = informal, used with तुम
• चाकू पर नज़र रखिए।
  = polite, used with आप

If you wanted to make it even softer, you could add words like:

• कृपया चाकू पर नज़र रखिए। = Please keep an eye on the knife.
• ज़रा चाकू पर नज़र रखिए। = Just keep an eye on the knife for a moment.

Not visibly in this sentence.

Yes, नज़र is generally treated as a feminine noun, but in चाकू पर नज़र रखिए, that does not create an obvious change in the form you see.

The important thing for a learner is:

• learn नज़र रखना as a whole expression
• do not worry too much about noun gender in this particular sentence

So even though gender exists in Hindi, the main thing here is understanding the idiom and the polite imperative form.

You could hear it in situations where someone wants another person to monitor a knife or make sure it does not go missing or get misused.

For example:

• in a kitchen
• around children
• in a shop
• during travel or security situations
• when someone has put a knife down and wants another person to watch it

So it sounds practical and situational, not literary or unusual.