Augmentatives: Suffixes -ina and -etina
In Croatian, you can emphasize that something is massive, imposing, or slightly monstrous by adding an augmentative suffix to a noun. The most common suffixes for this are -ina and -etina.
For example, a normal hand (ruka) becomes a huge, meaty hand (ručetina), and a regular forest (šuma) becomes a vast, imposing wilderness (šumetina).
Strict Feminine Singular Agreement
Here is the most important rule for augmentatives ending in -a: they are always grammatically feminine. This applies regardless of the original noun's gender, and it even applies regardless of the natural gender of the person being described.
Take the word for a huge, hulking man: ljudina.
Even though it describes a man, the noun itself acts entirely as a feminine noun. Any adjectives describing him, pronouns pointing to him, and past-tense verbs matching his actions must take the feminine singular form.
Notice in the following sentences how "that big guy" uses the feminine pronoun ta, and the verbs uzela and otišla end in -a.
Shifting Grammatical Genders
This strict feminine agreement means that many masculine nouns completely change their grammatical gender when they become massive. A masculine wolf (vuk) becomes a feminine huge wolf (vučina). A masculine stone (kamen) becomes a feminine huge stone (kamenčina). A masculine dog (pas) becomes a feminine huge dog (psina).
Augmentatives in Other Cases
Because these augmentatives follow the standard declension for feminine nouns ending in -a, they behave exactly like regular feminine nouns in all other grammatical cases. For example, when they are the direct object of a sentence (the accusative case), their -a ending becomes a -u, just as you would expect.