Possessive Adjectives From Feminine Nouns: matčin

Czech can turn a noun for a specific person directly into a possessive adjective — instead of saying "the book of my mother," it builds a one-word adjective meaning "mother's." From a feminine person-noun this adjective is formed with the suffix -in (with the endings -in / -ina / -ino), and the suffix almost always softens the consonant in front of it: matka (mother) → matčin (mother's), sestra (sister) → sestřin (sister's). This page covers how to build these forms, the stem changes they trigger, and how they fit into the larger possessive-adjective system alongside the masculine -ův series.

The basic idea: a noun becomes an adjective

A possessive adjective answers whose? with a single dedicated word, and it is restricted to a single, definite, usually animate possessor: a named person, a family member, a specific individual. You cannot build one from a plural or an indefinite group — for those you use the genitive instead.

From a feminine noun you take the stem, soften it, and add -in in the masculine form:

The consonant softening is the heart of it

The English-speaker's instinct is to leave the stem alone and just glue -in on: matkin. That is wrong. The -in suffix is "soft" and triggers the same alternation table you meet all over Czech grammar:

Watch babička → babiččin carefully: it already has a č in the stem (babič-ka), and the k of -ka softens to a second č, so you get the double čč: babiččin. Learners routinely drop one and write babičin; the spelling really is babiččin.

Agreement: -in, -ina, -ino

A possessive adjective is still an adjective, so it agrees with the thing possessed, not with the possessor. The bare suffix has three nominative-singular forms, one per gender of the possessed noun:

So whether you say matčin, matčina, or matčino depends entirely on the gender of what mother owns — never on mother herself. This is the reverse of the English logic, where 's attaches to the owner and never reacts to the thing owned: mother's house, mother's book, mother's car all keep the same 's. In Czech the suffix is half noun (it reads the possessor's gender to pick -in over -ův) and half adjective (it reads the possessed noun's gender to pick -in, -ina, or -ino). Both halves are alive at once, which is exactly why a single English 's corresponds to a small paradigm of Czech forms.

Mixed declension: short here, long there

Possessive adjectives use a mixed (hybrid) declension. In the most frequent cases — the nominative and the inanimate accusative — they use short noun-like endings (the ones in the table above: -in, -ina, -ino). In all the remaining cases they switch to long, regular adjective endings (-ina, -ino, -iným...), exactly like a normal hard adjective such as mladý.

The practical upshot is that you only ever have to memorize the short nominative/accusative forms as special; everything else behaves like the familiar adjective mladý once you carry the softened stem along. So matčin in the nominative becomes the wholly regular matčiného, matčinému, matčiným in the oblique cases — the same endings you would put on any hard adjective. The stem alternation (matk- → matč-) happens once, when you build the adjective, and then stays fixed through the entire declension; it does not re-trigger case by case.

One system, two suffixes: -in vs -ův

The feminine -in series is the mirror image of the masculine -ův series. They are not two unrelated rules; they are one system keyed to the gender of the possessor:

The endings on the right (the agreement with the possessed noun) are nearly identical between the two series — -a for feminine things, -o for neuter things. The only difference is the suffix vowel that encodes who owns it: o for a male owner, i for a female owner. Once you see this, the two pages stop being two rules and become one. Compare the full masculine treatment on the otcův page.

When NOT to use it: use the genitive instead

The possessive adjective only works for a single, definite, usually personal owner. The moment the owner is plural, modified, or non-personal, you switch to the genitive of the noun:

• kniha mých sester — "my sisters'(plural) book" → genitive, because the owner is plural.
• kniha té učitelky — "that teacher's book" → genitive, because the owner carries a modifier (té).

For the full contrast, see possessive adjective vs the genitive.

Common Mistakes

Key Takeaways

• A feminine personal noun becomes a possessive adjective with -in / -ina / -ino, agreeing with the thing owned.
• The suffix softens the stem consonant: k→č (matčin, babiččin), r→ř (sestřin, Petřin), ch→š (snašin), h→ž (Olžin).
• babička gives the double-č form babiččin — don't drop a č.
• These use a mixed declension: short endings in the nominative/accusative, long adjective endings elsewhere.
• -in (female owner) and -ův (male owner) are one system split by the possessor's gender.