This is the 281st most frequent Croatian word.
njemu
"Him" (dative case of "on" - he).
'Njemu' is used in the locative case here, referring to the subject of conversation.
Pričao sam o njemu.
I talked about him.
'Njemu' is used in the dative case here, indicating the recipient of the action of giving.
Dao sam njemu knjigu.
I gave the book to him.
'Njemu' is used in the dative case here, indicating the entity that is trusted.