אסור לעבור את הכביש כשהרמזור אדום.

אסור means forbidden or not allowed.

In this kind of sentence, Hebrew uses אסור + infinitive to mean it is forbidden to... or you must not...

So:

• אסור לעבור = it is forbidden to cross / you must not cross

This is a very common pattern in Hebrew:

• אסור לעשן = smoking is forbidden / you must not smoke
• אסור לדבר = talking is forbidden / you must not talk

It is an impersonal structure, so there is no separate word for it is.

Because after אסור, Hebrew normally uses the infinitive.

• לעבור = to cross / to pass

So the pattern is:

• אסור + infinitive

Examples:

• אסור להיכנס = it is forbidden to enter
• אסור לגעת = it is forbidden to touch
• אסור לעבור = it is forbidden to cross

This is similar to English forbidden to cross, not forbidden crosses or forbidden crossing.

את marks a definite direct object.

In this sentence, הכביש is the thing being crossed, and it is definite because it has ה־ (the), so Hebrew adds את before it:

• לעבור את הכביש

Important points:

• את usually does not have a direct English translation.
• It appears before a direct object that is definite: a noun with ה־, a name, a pronoun, etc.

Compare:

• לעבור כביש = to cross a road
• לעבור את הכביש = to cross the road

הכביש means the road, while כביש means a road or road in a more general sense.

In this sentence, the road is treated as a specific, identifiable thing in the situation, so Hebrew uses the definite form:

• הכביש = the road

This is very natural in both Hebrew and English with this type of statement:

• Don’t cross the road when the light is red
• אסור לעבור את הכביש כשהרמזור אדום

If you said לעבור כביש, it would sound more general, like to cross a road.

כשהרמזור means when the traffic light...

It is made from:

• כש = when
• הרמזור = the traffic light

So:

• כש + הרמזור = כשהרמזור

This is a very common Hebrew contraction. כש is often a shortened form of כאשר.

Examples:

• כשהוא בא = when he comes
• כשהילד ישן = when the child is asleep
• כשהרמזור אדום = when the traffic light is red

In the present tense, Hebrew usually does not use a separate word for is / am / are.

So:

• הרמזור אדום literally looks like the traffic light red
• but it means the traffic light is red

This is normal Hebrew.

More examples:

• הוא עייף = he is tired
• הדלת פתוחה = the door is open
• המים קרים = the water is cold

If the sentence were in the past or future, Hebrew would use a form of to be:

• הרמזור היה אדום = the traffic light was red
• הרמזור יהיה אדום = the traffic light will be red

Because adjectives in Hebrew agree with the noun in gender and number.

• רמזור is masculine singular
• so the adjective must also be masculine singular
• therefore: אדום

Compare:

• רמזור אדום = a red traffic light
• מכונית אדומה = a red car

If the noun were feminine, you would use אדומה.

Both can be used, but there is a nuance.

• לעבור את הכביש is common and natural in everyday speech.
• לחצות את הכביש is more specifically to cross from one side to the other.

So:

• אסור לעבור את הכביש sounds natural.
• אסור לחצות את הכביש would also be very natural.

If you are learning standard vocabulary, it is useful to know both:

• לעבור = to pass, go through, cross
• לחצות = to cross

With roads and streets, לחצות is especially precise, but לעבור is also widely used.

A close word-for-word breakdown is:

• אסור = forbidden
• לעבור = to cross
• את = direct object marker
• הכביש = the road
• כשהרמזור = when the traffic light
• אדום = red

So the literal structure is roughly:

Forbidden to cross the road when the traffic light red.

This sounds incomplete in English, but it is perfectly normal in Hebrew because present-tense is is omitted.

Because the sentence is built around the idea it is forbidden.

Hebrew often begins this kind of sentence with the predicate:

• אסור לעבור... = it is forbidden to cross...
• מותר להיכנס... = it is permitted to enter...
• כדאי לנסות... = it is כדאי / advisable to try...

So the focus comes first: the rule or evaluation.

This is very idiomatic Hebrew and is one of the most common ways to express prohibition.

A simple transliteration is:

Asur la'avor et ha-kvish ksheha-ramzor adom.

A rough pronunciation guide:

• אסור = ah-SOOR
• לעבור = lah-ah-VOR
• את = et
• הכביש = hah-kVEESH
• כשהרמזור = ksheh-hah-rahm-ZOR
• אדום = ah-DOM

Approximate full pronunciation:

ah-SOOR lah-ah-VOR et hah-kVEESH ksheh-hah-rahm-ZOR ah-DOM

The stress is usually near the end in these words:

• אסור
• לעבור
• רמזור
• אדום