Possessive adjectives: Petrův, Janin
Petrovo auto, Janina sestra, mámin dům
In short
To say Petr's or Mum's, Czech often turns the person into an adjective: Petr → Petrův, Jana → Janin. It agrees with the thing that's owned: Petrův dům, Petrova kniha, Petrovo auto. You can also use the genitive (auto Petra), but the adjective is what you'll hear most.
- Petrovo autoPetr's car
- Janina sestraJana's sister
- Tátův důmDad's house
- mámina knihaMum's book
Full explanation
| Owner | Masculine thing | Feminine thing | Neuter thing | Plural |
|---|---|---|---|---|
| a man: Petr, táta | Petrův dům | Petrova kniha | Petrovo auto | Petrovy klíče |
| a woman: Jana, máma | Janin dům | Janina kniha | Janino auto | Janiny klíče |
- For men, add -ův; for women, swap the -a for -in.
- Sound changes: sestra → sestřin, babička → babiččin, Monika → Moničin. And e can drop out: Pavel → Pavlův.
- Men ending in -a take -ův too: táta → tátův, Mucha → Muchův.
- In the other cases they mostly take adjective endings: v Petrově bytě, jet Petrovým autem, s Janinou sestrou, do Petrova pokoje.
They're only for one specific person. As soon as there's another word with the owner, use the genitive: auto mého bratra, not "můj bratrův".
Women's surnames in -ová come from the same idea: Nováková originally meant "Novák's (wife or daughter)".