svůj

1. How it works:
Svůj replaces words like můj (my), tvůj (your), jeho (his), její (her), and jejich (their) whenever the possessor is the subject of the clause.

2. Declension and Register:
It declines exactly like můj and must agree with the possessed noun in gender, number, and case. Crucially, svůj changes its form based ONLY on the object being owned, not the person who owns it. For certain forms, everyday spoken Czech often uses longer forms, while formal written Czech prefers contracted forms. For example, the feminine accusative can be svoji (spoken, short i) or svou (formal), and the feminine instrumental can be svojí (spoken, long í) or svou (formal). Neuter and plural nominative/accusative often use svoje (spoken) or své (formal). In everyday spoken Czech, you will also hear variants like svýho (for svého), svýmu (for svému), and svým (for svém).

3. The Golden Rule:
Because svůj points back to the subject, it cannot be part of the subject itself. You cannot say "Svůj bratr je doktor" (His own brother is a doctor). You must use regular possessive pronouns like Jeho bratr or Můj bratr.

4. Used for All Persons:
While it's most critical in the third person to avoid confusion, native speakers use svůj for all persons (I, you, we, they). Saying "Mám můj klíč" instead of "Mám svůj klíč" sounds unnatural unless you are specifically emphasizing contrast (e.g., "I have my key, not yours").

5. Shared Ownership Exception:
For the first and second person plural (my and vy), svůj is not used if the subject shares ownership with a wider group (like a nation or a team). For example, it is more natural to say "Fandíme našim sportovcům" (We cheer for our athletes) or "Chráníme naši vlast" (We protect our homeland) instead of using svým or svou.

6. Idiomatic Usage:
You might also hear svůj used as an adjective to describe someone who is peculiar, independent, or acting like themselves. For example, "On je takový svůj" means "He is a bit peculiar" or "He is his own man".

7. Body Parts and Clothing:
English speakers tend to overuse possessive pronouns. In Czech, when talking about body parts, clothing, or personal routines, you usually drop the possessive entirely. Instead of saying "Myju svoje ruce" (I wash my hands), Czechs use a reflexive pronoun and the bare noun, like "Myju si ruce".

8. Imperatives (Commands):
When giving a command, the subject (you) is implied. Therefore, you must use svůj when telling someone to do something with their own belongings. For example, "Vezmi si svůj kabát" (Take your coat).

9. Subordinate Clauses:
Svůj only points to the subject of its own specific clause. If a sentence has multiple clauses, pay attention to the subject of each one. For example, in "Petr řekl, že jeho bratr přijde" (Petr said that his brother will come), you must use jeho because the subject of the second clause is the brother, not Petr.