Feminine consonant-ending nouns: Instrumental (-i, -ju, -ću)

Feminine nouns ending in a consonant have two distinct forms in the instrumental singular. The form you use usually depends on whether the noun stands alone or is modified by an adjective or pronoun.

The Standalone Ending: Jotation (-ju)

When a feminine consonant-ending noun stands alone (without any descriptive words attached to it), it typically takes the ending -ju.

Adding -ju directly to a consonant triggers a sound change known as jotation (merging the final consonant with the j).

• For abstract nouns ending in -st (such as ludost or svijest), the combination of -st
  • -ju becomes -šću (ludošću, sviješću).
• For nouns ending in -v (like ljubav), the combination becomes -vlju (ljubavlju).

Note on usage: The instrumental case is used directly (without a preposition) after verbs like ponositi se (to be proud of), baviti se (to deal with), and upravljati (to manage). It also follows the preposition s / sa (with) to describe the manner in which an action is performed.

The Modified Ending (-i)

The rules become much simpler when you add a descriptive word. If the noun is accompanied by an adjective or a pronoun (like "my", "that", or "deep"), the complex jotated ending is usually dropped.

Instead, modified nouns take the simple -i ending. This makes their instrumental singular identical to their genitive, dative, and locative singular forms.