Learn Croatian: Međutim, ispričali su se predostrožnosti radi. - However, they apologized for the sake of precaution.

In standard Croatian, the preposition radi (meaning for the sake of) usually comes before the noun. However, for stylistic emphasis, it can be placed immediately after a bare Genitive noun. Phrases like predostrožnosti radi act as fixed, slightly formal expressions, similar to saying 'just to be on the safe side' or 'as a precaution'.

Why does the noun predostrožnost end in -i here?

The word predostrožnost (precaution) is a feminine noun that ends in a consonant, which means it belongs to the i-declension group. Because the word radi requires the Genitive case, we add -i to the end, making it predostrožnosti.

Would the sentence mean something else if we removed the word se?

Yes, it would completely change the meaning. The verb for to apologize is the reflexive ispričati se. Without se, the verb ispričati means to narrate or to tell a story to the end.

Why are the enclitics su se placed after ispričali rather than after Međutim?

Enclitics usually take the second position in a sentence. Here, Međutim (However) is treated as an introductory word and separated by a comma, creating a pause. Because of this pause, the enclitics cannot attach to it and instead must attach to the first word of the actual main clause, which is ispričali.