Learn Hardcore Polish: On idzie na spacer bez niej. - He is going for a walk without her.

Iść (infinitive) is what you’d see in a dictionary, but in a real sentence you must conjugate it. There is no form idzieć in standard Polish; that’s just a common learner’s error influenced by patterns like widzieć (to see).

What is the difference between On idzie na spacer and On chodzi na spacer?

Polish distinguishes between one specific movement now and habitual / repeated movement:

iść → idzie
- Focus: one particular action happening now or in the near future.
- On idzie na spacer. = He is going for a walk (right now / on this specific occasion).
chodzić → chodzi
- Focus: repeated, habitual, general activity, “he tends to do this”.
- On chodzi na spacer. = He goes for walks (regularly / in general).

So:

If you imagine him leaving the house right now: On idzie na spacer.
If you’re talking about his routine: On chodzi na spacer.

Why do we say na spacer and not something like do spaceru or just spacer?

In Polish, na + accusative is very often used to express going somewhere for some activity:

iść na spacer – to go for a walk
iść na zakupy – to go shopping
iść na obiad – to go (for) lunch
iść na spotkanie – to go to a meeting

So na spacer literally is “onto/for a walk”, but idiomatically it just means for a walk.

Do spaceru is not used in this context; do + genitive usually means to (a place/person), not an activity like this.

Why is it bez niej and not bez ona or bez ją or bez nią?

The key points:

Bez (without) always takes the genitive case.
The feminine pronoun she / her in genitive (stressed form) is niej.

Relevant forms of the feminine pronoun:

Nominative (subject): ona – she
Accusative / Genitive (unstressed): jej – her
Genitive (stressed, after prepositions): niej – her
Instrumental: nią – (with) her

After bez we need genitive, and with a preposition and emphasis we use the stressed form:

bez kogo? – without whom? → bez niej – without her

So:

bez ona – wrong case (nominative instead of genitive)
bez ją – wrong case and form (accusative form plus wrong ending)
bez nią – wrong case (instrumental; would go with z, not bez)

Correct: bez niej.

What is the difference between niej, nią, and jej?

They are all forms of she / her, but in different cases and with different uses:

ona – nominative (subject): Ona idzie. – She is going.
jej – genitive / dative / possessive (unstressed):
- Genitive: Nie ma jej. – She is not there / She’s missing.
- Dative: Daj jej książkę. – Give her the book.
- Possessive: jej książka – her book.
niej – stressed form used in genitive / locative after prepositions:
- Genitive after bez: bez niej – without her
- Locative after o: myśleć o niej – to think about her
nią – instrumental (often after z) and sometimes accusative in spoken language:
- Instrumental: z nią – with her
- Also: Interesuję się nią. – I’m interested in her.

In our sentence, we need genitive after a preposition (bez) and we want the stressed form, so niej is correct: bez niej.

Can I drop On and just say Idzie na spacer bez niej?

Yes, and this is actually very natural in Polish.

Polish is a pro-drop language, meaning the subject pronoun is often omitted when it is clear from the verb form:

On idzie na spacer bez niej. – He is going for a walk without her.
Idzie na spacer bez niej. – (He) is going for a walk without her.

The verb ending -e in idzie already tells us it’s he / she / it. Context usually makes clear who we mean. You keep On only when you want to emphasize he (contrast, clarity, or style).

Can I change the word order, for example On bez niej idzie na spacer or Na spacer on idzie bez niej?

Yes, Polish word order is fairly flexible, but changes can add emphasis or sound more/less natural.

All of these are grammatically correct:

On idzie na spacer bez niej.
- Neutral, most typical order. Emphasis is fairly balanced.
On bez niej idzie na spacer.
- Slight emphasis on bez niej; you’re bringing without her closer to the verb, e.g. correcting someone:
  - Nie, nie idą razem. On bez niej idzie na spacer.
    No, they’re not going together. He is going for a walk without her.
Na spacer on idzie bez niej.
- Fronts na spacer (for a walk), can sound a bit more stylistic, contrastive or poetic. For example:
  - Na spacer on idzie bez niej, nie do kina.
    He’s going for a walk without her, not to the cinema.

In everyday speech, (1) is the most neutral and common.

Is idzie present or future? Does it mean “he is going” or “he will go”?

Formally, idzie is present tense of iść.

However, in Polish, present tense of motion verbs very often refers to the near future, just like English He is going tomorrow can be future.

Depending on context:

On idzie na spacer (teraz). – He is going for a walk (now).
On jutro idzie na spacer. – He is going / will go for a walk tomorrow.

So grammatically: present tense.
Semantically: present or near future, depending on time expressions and context.

What verb would I use if he is going by car, not on foot? Is idzie still correct?

No. Idzie specifically means goes on foot.

For vehicles, you use jechać / jeździć:

jechać (one specific trip by vehicle) → on jedzie – he is going (by car/bus/train etc.) (now / this time)
jeździć (habitually by vehicle) → on jeździ – he goes (by car, in general / regularly)

So:

On idzie na spacer. – He is going for a walk (on foot).
On jedzie do pracy. – He is going to work (by car / bus / etc.).

If you really mean for a walk, by definition it is usually on foot, so idzie is the natural verb.

Why is it na spacer (accusative) and not na spacerze (locative)?

Na can take accusative or locative, depending on the meaning:

na + accusative → movement towards a place/activity:
- iść na spacer – to go for a walk
- iść na plażę – to go to the beach
- iść na koncert – to go to a concert
na + locative → location at/on:
- być na spacerze – to be on a walk
- leżeć na plaży – to lie on the beach
- być na koncercie – to be at a concert

So:

On idzie na spacer. – He is going (movement) for a walk.
On jest na spacerze. – He is (currently) on a walk.

In your sentence, there is movement, so na spacer (accusative) is correct.

How would I say “without them / without us / without me” instead of “without her”?

You keep bez and change the pronoun to the genitive form:

bez niej – without her
bez niego – without him
bez nich – without them
bez nas – without us
bez mnie – without me
bez ciebie – without you (singular)
bez was – without you (plural)

Examples with the original sentence:

On idzie na spacer bez niej. – He is going for a walk without her.
On idzie na spacer bez nich. – He is going for a walk without them.
On idzie na spacer bez nas. – He is going for a walk without us.
On idzie na spacer bez mnie. – He is going for a walk without me.