Njegova ideja je različita od moje.

His idea is different from mine.

Breakdown of Njegova ideja je različita od moje.

• biti: to be
• njegov: his
• ideja: idea
• različit: different

Questions & Answers about Njegova ideja je različita od moje.

Why is it različita, not različit?

Because it agrees with the subject ideja, which is feminine singular. Predicate adjectives in Croatian agree in gender and number with the subject:

• masculine: različit
• feminine: različita
• neuter: različito
• plural: različiti/različite (masc/fem)

What case is moje here, and why?

It’s feminine genitive singular. The preposition od (“from/than” in comparisons) always takes the genitive, so “my” must be in genitive to match the understood noun (ideje): od moje (ideje).

Why can moje stand alone without repeating ideja?

Croatian often omits a repeated noun when it’s clear from context. Od moje is a shorthand for od moje ideje. The form of moje tells you which gender/number/case the omitted noun would have.

Why not say od moja or od moj?

Because od requires genitive. Moja is nominative feminine singular; moj is nominative masculine singular. You need the genitive feminine singular: moje.