This is the 782nd most frequent Croatian word.
supruga
Wife.
Suprugom is used here in instrumental case, indicating participation in the activity together with Ivan's wife.
Idemo na večeru s Ivanovom suprugom.
We are going to dinner with Ivan's wife.
Supruga is used here as the subject of the sentence, referring to the speaker's wife.
Moja supruga voli kuhati.
My wife loves to cook.
Supruzi is in dative case here, indicating the recipient of the action.