Proverb: Куй желе́зо, пока́ горячо́

This proverb is the Russian "strike while the iron is hot", and like the English it comes from the smithy: heat fades fast, so you must hammer in the brief window while the metal glows. Grammatically it is a compact teaching machine. It shows why an imperfective imperative (Куй) is right for standing, general advice; how the conjunction пока́ ("while") frames a window of opportunity; and how Russian builds an impersonal predicate — горячо́, "[it is] hot" — with no subject and no verb "to be". Add the accusative object желе́зо and you have four grammar points in three words.

The proverb

Word by word

The literal skeleton is "Forge [the] iron, while [it is] hot." Russian needs no "it", no "is", and no "the".

Куй — the imperfective imperative for general advice

Куй is the singular (ты-form) imperative of кова́ть ("to forge, to hammer / work metal"). Its imperative is mildly irregular: the present stem is ку- (кую́, куёшь, кую́т), and the imperative adds -й → куй (the plural/polite form is ку́йте).

The key teaching point is aspect. Кова́ть is imperfective, and the proverb deliberately uses the imperfective imperative — even though "strike!" might feel like a single sharp command. Why? Because imperfective imperatives express general, repeated, or open-ended instruction — advice about how to act in general, as a rule of life — whereas perfective imperatives push for one specific, completed action right now. A proverb is precisely a piece of standing, all-purpose wisdom: "(whenever the chance comes,) hammer away while it's hot." That repeated, advisory sense is exactly what the imperfective imperative carries. A perfective Скуй желе́зо would mean "forge this one piece of iron (to completion)" — a concrete order, not a maxim.

желе́зо — the accusative object

желе́зо ("iron") is the direct object of куй — the thing you hammer — so it stands in the accusative. Because желе́зо is a neuter inanimate noun, its accusative is identical to its nominative (желе́зо → желе́зо); the case is real but invisible. The role is unmistakable from the transitive verb: куй ("forge") takes a thing to be forged, and that thing is the accusative желе́зо. (If you swapped in a feminine noun the accusative would show: Куй ло́шадь would become problematic for sense, but a phrase like куй подко́ву "forge a horseshoe" shows the feminine accusative подко́ву from подко́ва.)

пока́ горячо́ — "while [it is] hot"

The second clause is where Russian diverges sharply from English.

пока́ is the temporal conjunction "while / as long as". It opens the window during which the advice holds: forge it while it's still hot, because the moment will pass. (Пока́ doubles as a casual "bye!" in conversation, but here it is the full conjunction.) Пока́ introduces a clause that runs simultaneously with the main one — the hammering and the heat coexist.

горячо́ is the striking part: it is an impersonal short-form predicate meaning "[it is] hot", and it has no subject and no verb. Three things are happening:

1. It is a short-form / adverbial neuter, not a full adjective. The full adjective "hot" is горя́чий (masc.) / горя́чая (fem.) / горя́чее (neut.). The form горячо́ is the neuter short form, which Russian uses as an impersonal predicate describing a state of affairs in general — "it is hot (around here / right now)". This is the same family as хо́лодно ("it's cold"), тру́дно ("it's hard"), по́здно ("it's late").
2. There is no "it". English requires a dummy subject — "while it is hot". Russian has none; горячо́ stands alone and is grammatically subjectless. The neuter form is what marks the impersonal, "ambient state" reading.
3. There is no "is". As always in the Russian present, the copula is dropped. Горячо́ by itself = "(it) is hot".

Strictly, you could spell it out with a subject — пока́ оно́ горячо́ ("while it [the iron] is hot"), with оно́ referring back to neuter желе́зо and горячо́ now agreeing as a neuter short form. The proverb drops the оно́, leaving the leaner, more idiomatic impersonal горячо́. Either way the predicate is the short neuter form, never the full горя́чее.

What it means and when to say it

The proverb is advice to seize the moment — act now, while the conditions are favourable, before the chance cools and is lost. It is used to urge prompt action: take the opportunity, close the deal, ask the question, make your move now, because the window won't stay open. It is encouraging rather than scolding (unlike "you snooze, you lose"), and it's at home in business, romance, politics, and everyday nudging alike. Register-wise it is neutral and very common — you'll hear it in casual chat and read it in a newspaper column.

Vocabulary gloss

Common Mistakes

Key Takeaways

• Куй is the imperfective imperative of кова́ть — the imperfective fits a proverb's standing, general advice, not a one-off order (which would be perfective Скуй).
• желе́зо is the accusative direct object; being neuter, its accusative looks like the nominative — the transitive verb signals the role.
• пока́ = "while / as long as", framing the window of opportunity.
• горячо́ is an impersonal neuter short-form predicate ("[it is] hot") with no subject and no copula — like хо́лодно, тру́дно. Not the full adjective горя́чее.
• Meaning: seize the moment — act now, while conditions are favourable, before the chance cools.