Nif'al Infinitive (להיכנס) and Imperative (היכנס!) | Hebrew Grammar

The nif'al infinitive is the most useful diagnostic in the whole verb system: it opens להי־, and the only pa'al infinitive that does is להיות "to be". Learn that one exception and the test is yours: if you can say "to do it", you know which binyan you are holding.

Building it

ל־ + הִי + a doubled first root letter. The doubling is the assimilated נ of the binyan, exactly as in the future, and unpointed the chirik of that הִי takes a yod.

Verb	Pointed	Ktiv male	Reading
נכנס enter	לְהִכָּנֵס	להיכנס	lehikanés
נשאר stay	לְהִשָּׁאֵר	להישאר	lehisha'ér
נפגש meet up	לְהִפָּגֵשׁ	להיפגש	lehipagésh
נזהר be careful	לְהִזָּהֵר	להיזהר	lehizahér
נמצא be located	לְהִמָּצֵא	להימצא	lehimatsé
נבנה be built	לְהִבָּנוֹת	להיבנות	lehibanót

Where the first root letter is one of א, ה, ח, ע, ר no dagesh is possible, so the vowel lengthens to a tsere — and the yod stays in the spelling all the same:

Verb	Pointed	Ktiv male	Reading
נראה look, seem	לְהֵרָאוֹת	להיראות	lehera'ót
נרדם fall asleep	לְהֵרָדֵם	להירדם	leheradém
נעלם disappear	לְהֵעָלֵם	להיעלם	lehe'além
נחשב be considered	לְהֵחָשֵׁב	להיחשב	lehekhashév

אני מנסה להיכנס לחשבון כבר שעה ולא מצליחה.

aní menasá lehikanés lakheshbón kvar sha'á veló matslikhá

I've been trying to log into the account for an hour and I can't. (f. speaker)

עדיף להישאר בבית, הכביש פקוק לגמרי.

adíf lehisha'ér babáyit, hakvísh pakúk legamréi

Better to stay home — the road is completely jammed.

אני רוצה להיראות רצינית בראיון מחר.

aní rotsá lehera'ót retsinít bare'ayón makhár

I want to look serious in the interview tomorrow. (f. speaker)

Two published variants, so a dictionary disagreeing with you means nothing

Wherever the third root letter is a guttural — ח or ע — the verb has two accepted infinitives, and reference works differ over which to head the entry with: לְהִשָּׁמֵעַ beside לְהִשָּׁמַע "to be heard", לְהִפָּתֵחַ beside לְהִפָּתַח "to be opened", לְהִשָּׁלֵחַ beside לְהִשָּׁלַח "to be sent", לְהִקָּרֵעַ beside לְהִקָּרַע "to be torn". The patach member carries a matching future — יִפָּתַח, יִשָּׁמַע. Unpointed the two are one word (להישמע, להיפתח), so the variation is invisible in ordinary writing and you need only recognise it in a dictionary.

One verb is simply irregular: נהנה "enjoy" has the infinitive לֵהָנוֹת, written ליהנות — no הי־ at all. It belongs with the weak-root nif'al verbs.

החנות אמורה להיפתח מחדש בספטמבר.

hakhanút amurá lehipatéakh mekhadásh beseptémber

The shop is supposed to reopen in September.

One stem, two forms — so you get the infinitive free

The הי־ of the infinitive is the same element that carries the future. Take the future, strip the tense prefix, put לְהִי (or לְהֵי) in front, and you have the infinitive:

Future	Infinitive	Future	Infinitive
ייכנס	להיכנס	ייראה	להיראות
יישאר	להישאר	יירדם	להירדם

💡

Now use the yod as a diagnostic. The matching hif'il infinitive has no yod, so the same root gives two infinitives a single letter apart — and they mean opposite things. להיכנסlehikanés "go in" against להכניסlehakhnís "put in"; להישאר "stay" against להשאיר "leave behind"; להירדם "fall asleep" against להרדים "put to sleep". One is what you do; the other is what you do to something.

אפשר להיפגש מחר בערב או שאתה עסוק?

efshár lehipagésh makhár ba'érev o she'atá asúk?

Can we meet tomorrow evening, or are you busy? (to a man)

The true imperative

Drop the ל and you have it. The vowels do not change at all:

Verb	to a man	to a woman	to a group
נכנס	הִכָּנֵס · היכנסhikanés	הִכָּנְסִי · היכנסיhikansí	הִכָּנְסוּ · היכנסוhikansú
נזהר	הִזָּהֵר · היזהרhizahér	הִזָּהֲרִי · היזהריhizaharí	הִזָּהֲרוּ · היזהרוhizaharú
נרדם	הֵרָדֵם · הירדםheradém	הֵרָדְמִי · הירדמיheradmí	הֵרָדְמוּ · הירדמוheradmú

And now the honest part: you will almost never say these. Everyday spoken Hebrew gives orders with the future — תיכנס, תיזהר, תישארי כאן — and that is not sloppiness, it is the ordinary system. The forms in the table above belong to written and institutional Hebrew: printed instructions, formal invitations, army orders, safety notices, and the literary register.

תיזהר, המדרגה האחרונה גבוהה.

tizahér, hamadregá ha'akharoná gvohá

Careful — the last step is a big one. (informal, to a man: the everyday command is the future)

היכנסו בבקשה, הישיבה מתחילה בעוד רגע.

hikansú bevakashá, hayeshivá matkhilá be'ód réga

Please come in, the meeting starts in a moment. (formal — an announcement or a printed notice)

The register runs all the way back. הִשָּׁמֶר לְךָ פֶּן… — "take care lest you…" — is a fixed biblical formula, standing in Deuteronomy 8:11, Genesis 24:6 and Exodus 34:12, and it is still the shape a modern warning notice reaches for when it wants weight.

הישמר לך פן תשכח

hishámer lekhá pen tishkákh

Take care lest you forget. (literary/biblical — Deuteronomy 8:11; the modern citation form of the imperative is הִשָּׁמֵר hishamér)

Saying "don't"

A negative command is אל + the future, in every binyan and every register. There is no negative imperative in Hebrew: אל is never followed by one of the forms in the table above.

אל תיכנס לשם בלי קסדה.

al tikanés leshám bli kasdá

Don't go in there without a helmet. (to a man)

אל תישארי בחוץ, מתחיל לרדת גשם.

al tisha'arí bakhúts, matkhíl larédet géshem

Don't stay outside — it's starting to rain. (to a woman)

Impersonal written prohibitions take a third route, נא / אנא + the infinitive (נא לא לעשן), which addresses nobody in particular; that construction has its own page, infinitive as impersonal command.

Common Mistakes

1. Building the infinitive by putting ל on the dictionary form. Hebrew heads a verb with the past "he" — נכנס — and that form is not a stem you can prefix.

❌ אני מנסה לנכנס לחשבון

Incorrect — there is no such word. A nif'al infinitive is built on הי־ plus a doubled first root letter: להיכנס.

✅ אני מנסה להיכנס עם הסיסמה החדשה ולא עובד.

aní menasé lehikanés im hasismá hakhadashá veló ovéd

I'm trying to log in with the new password and it's not working. (m. speaker)

2. Leaving the yod out. The pointed text writes לְהִכָּנֵס, but unpointed Hebrew does not.

❌ אסור להכנס לאתר הבנייה

Incorrect as ktiv male — the chirik of the הִי stands before a doubled letter, so it takes a yod: להיכנס. להכנס is the pointed spelling with its niqqud stripped off.

✅ אסור להיכנס לאתר הבנייה בלי אישור.

asúr lehikanés la'atár habniyá bli ishúr

Entry to the building site is not allowed without a permit.

3. Negating a true imperative. אל takes the future, never an imperative form.

❌ אל היכנס בלי לדפוק

Incorrect — אל is never followed by an imperative form. A negative command is אל plus the future: אל תיכנס.

✅ אל תיכנס בלי לדפוק, יש שם פגישה.

al tikanés bli lidpók, yesh sham pgishá

Don't come in without knocking — there's a meeting going on in there. (to a man)

Key Takeaways

The infinitive is ל + הי + a doubled first root letter: להיכנס, להישאר, להיפגש, להיזהר. Nif'al infinitives open להי־ — ליהנות is the one that does not — and the only pa'al infinitive that looks the same is להיות. Rule that one word out and the test is reliable.
With א, ה, ח, ע, ר first there is no dagesh and the vowel is a tsere, but the yod stays: להיראות, להירדם, להיעלם, להיחשב.
The infinitive and the future share a stem: ייכנס → להיכנס, ייראה → להיראות.
One yod separates nif'al from hif'il: להיכנס "go in" against להכניס "put in"; להישאר against להשאיר.
The true imperative is the infinitive minus its ל — היכנס, היכנסי, היכנסו — and it belongs to written and formal Hebrew. Everyday speech commands with the future: תיכנס, תיזהר, תישארי.
A negative command is אל + future in all registers: אל תיכנס, אל תישארי. אל plus a true imperative does not exist.
A guttural third radical gives two published infinitives (לְהִשָּׁמֵעַ ~ לְהִשָּׁמַע, לְהִפָּתֵחַ ~ לְהִפָּתַח, לְהִשָּׁלֵחַ ~ לְהִשָּׁלַח) — one word unpointed either way — and ליהנות is irregular.

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