Genitive Plural: The Hard Case

If the genitive singular is the easiest oblique case, the genitive plural is the one that defeats learners — and even trips up native writers under time pressure. It is hard for two compounding reasons: a three-way ending split (-a, -i, -iju) that does not map cleanly onto gender, and a fleeting vowel that materialises inside the stem of many feminine and neuter nouns. This page does not give you a list to memorise; it gives you a decision procedure plus the short list of genuine irregulars you simply have to know.

The default ending: long -a

For the great majority of nouns — all masculines, neuters, and the big feminine -a class — the genitive plural ends in -a. The catch that makes it sneaky is length: this -a is long, while several other -a forms in the paradigm are short. Croatian spelling does not mark the difference, so žena (genitive singular, short -a) and žena (genitive plural, long -a) are written identically and distinguished only by vowel length in speech. Often that length is the only audible signal that you are in the genitive plural at all.

The fleeting vowel: -a- splits a cluster

Here is the first real difficulty. Many feminine -a and neuter nouns lose their ending entirely in the genitive plural, exposing a stem that ends in an awkward consonant cluster. Croatian rescues the pronunciation by inserting a fleeting -a- (nepostojano a) between the last two consonants:

The rule is mechanical: if dropping the ending would leave a hard-to-pronounce cluster, slip in -a-; if the resulting form is already pronounceable, leave it alone (žena → žena, knjiga → knjiga, no insertion needed). Note that this -a- lands inside the word — sestara, not sestra — and that the genitive plural -a is then added on top, giving forms with two a's at the end region (sest-a-r-a). The mechanism is treated in full on the fleeting -a- page.

The -i ending: i-declension feminines and a set of nouns

The consonant-final feminine i-declension takes -i in the genitive plural — the same -i that runs through most of its singular paradigm, so the form looks unchanged from the nominative plural:

Beyond the i-declension, a scattered set of masculine and other nouns also take -i in the genitive plural — these you learn item by item. The two you will meet earliest are ljudi ("people," genitive plural also ljudi, unchanged) and mjesec ("month," genitive plural mjeseci):

The -iju ending: relics of the old dual

The hardest and smallest group takes -iju, a frozen remnant of the ancient dual number (the form for "two of something"). It clusters, fittingly, around paired body parts and a few high-frequency nouns. These are not predictable — they are a memorise-list:

Two cautions on this group. First, oko and uho not only take -iju but change their stem (k → č, h → š): oko → očiju, uho → ušiju — these are doubly irregular and must be memorised whole. Second, ruka and noga keep the bare dual form ruku and nogu (no -iju in the modern standard), which happen to look like the accusative singular — context disambiguates.

The decision procedure

Rather than memorising hundreds of forms, run a noun through these questions:

1. Is it an i-declension feminine (consonant-final feminine: noć, stvar, ljubav)? → ending is -i (noći, stvari, ljubavi).
2. Is it on the short -iju / dual list (oko, uho, prst, gost, ruka, noga and a few more)? → use the memorised form (očiju, ušiju, prstiju, gostiju, ruku, nogu).
3. Is it a masculine on the -i sublist (ljudi, mjeseci, …)? → ending is -i.
4. Otherwise (the default — most masculines, neuters, feminine -a nouns) → ending is long -a; then check whether dropping the old ending leaves an ugly cluster, and if so insert the fleeting -a- (sestr- → sestara, pism- → pisama).

Common Mistakes

Key Takeaways

• The default genitive plural is long -a — and its length is invisible in spelling, so it can be the only signal that you are in this case.
• A fleeting -a- is inserted to break consonant clusters in many feminine -a and neuter nouns: sestara, pisama, djevojaka.
• i-declension feminines and a set of nouns take -i: noći, stvari, ljudi, mjeseci.
• A small -iju / dual-relic group is must-memorise: očiju, ušiju, prstiju, gostiju, ruku, nogu (and oko, uho also change their stem).
• Run the four-step procedure, and remember that everything from five up and quantifiers like puno/mnogo send the noun here.