Learn Hardcore Japanese: kare ha zenzen tikokusinai.

全然 (zenzen) is an adverb meaning “completely/at all.” With a negative predicate like しない, it means “not at all/never.” So 彼は全然遅刻しない means “He is never late” or “He doesn’t come late at all.”
It does not take a particle. Don’t say 全然に.
Colloquially, 全然 is also used with positives (e.g., 全然大丈夫 “totally fine”), but in careful writing it’s most standard with negatives.

Is the nuance really “never,” not just “rarely”?

Yes, in this sentence 全然 + しない strongly implies “never (as a habit).”
If you want “rarely/seldom,” use:
- めったに遅刻しない (rarely)
- ほとんど遅刻しない (almost never)
- あまり遅刻しない (not often)

Why is は used after 彼? Could I use が instead?

は marks the topic: “As for him, he never is late.” It’s the neutral way to make a general statement about him.
が marks the subject for focus/new information. 彼が全然遅刻しない is used when emphasizing “he (as opposed to someone else) is the one who never is late,” or inside a larger sentence (e.g., 彼が全然遅刻しない人だ “He is a person who never is late”).

Can I omit 彼? Is it natural to say just 全然遅刻しない?

Yes. Japanese often drops the subject when it’s clear from context. 全然遅刻しない by itself is natural in a conversation where “he” is understood.
In real conversations, using the person’s name + さん or just context is more natural than 彼, especially if he’s present.

What’s the difference between 遅刻する, 遅れる, and 遅くなる?

遅刻する (chikoku-suru): “to be tardy/late (for school, work, a meeting).” Person + は/が; event + に.
- 例: 会議に遅刻する “be late for a meeting.”
遅れる (okureru): “to be delayed/be late.” Used for people or things (like trains); event + に.
- 例: 電車が遅れる “The train is delayed.” 授業に遅れないようにする “Try not to be late to class.”
遅くなる (osoku naru): “to become late (time gets late)/come home late.”
- 例: 帰るのが遅くなる “I’ll come home late.”

Can I say 遅刻をしない? Do I need を with this する-noun?

Both 遅刻しない and 遅刻をしない are grammatically correct. The を version is a bit more formal/bookish; everyday speech usually drops を: 遅刻する/しない.
When you specify what you’re late for, use に on the event: 授業に遅刻する. Avoid 授業に遅刻をする, which sounds clunky.

Where should 全然 go? Is 遅刻を全然しない okay?

The most natural placement is just before the predicate: 全然遅刻しない.
遅刻を全然しない and 全然遅刻をしない are possible but sound more marked/bookish or emphatic. Default to 全然遅刻しない.

How do I make this sentence polite?

Polite: 彼は全然遅刻しません.
If you need honorifics for the subject (e.g., a superior), you can say 彼は遅刻なさいません. Combining honorifics with 全然 is possible but can feel a bit heavy; 彼はほとんど遅刻なさいません is a safer, softer compliment.

How do I say “He has never been late (even once)”?

Use the experience pattern 〜たことがない:
- 彼は一度も遅刻したことがない. (“He has never been late, not even once.”)
- 今まで遅刻したことがない adds “up to now.”

What’s the difference between しない and していない here?

しない is the plain non-past negative: general/habitual or future-negative (“doesn’t/never does/won’t do”).
していない is progressive/state: “is not doing/has not been doing (currently/around now).”
- 遅刻していない means “(he) is not late (now)” or “hasn’t been late (recently, in the ongoing timeframe),” not the habitual “never late.”

How do I say “He is never late to class/work/meetings” with this pattern?

Mark the event with に:
- 彼は授業に全然遅刻しない. (class)
- 彼は会社に全然遅刻しない. (to the company/workplace)
- 彼は会議に全然遅刻しない. (meetings)

Is it okay to use 全然 in positive sentences like 全然大丈夫?

Yes, in casual speech: 全然大丈夫/全然いい/全然できる. It means “totally/completely.”
In formal writing or exams, some teachers still prefer 全然 with negatives only. With negatives (as in your sentence), it’s always safe.

What are alternatives to 全然 for “not at all/never,” and how do they differ?

What would 彼は遅刻はしない mean compared to 彼は全然遅刻しない?

遅刻はしない uses contrastive は on 遅刻: “He doesn’t (at least) ever be late” (implying contrast, e.g., he might have other issues). It highlights tardiness as the specific thing he doesn’t do.
全然遅刻しない is a straightforward emphatic “never (late).”

Are the spaces between words normal in Japanese?

No. Standard Japanese writing doesn’t insert spaces between words. They’re sometimes added in teaching materials. The natural sentence is 彼は全然遅刻しない。

Do I ever need に after 全然 (like 全然に)?

No. 全然 is an adverb and never takes に. Just place 全然 before the negative predicate: 全然〜ない.