This is the 596th most frequent Estonian word.
indrek
"Indrek" is a male given name in Estonia.
The word 'Indrek' is a proper noun here and is in an elative case form ('Indrekust') to indicate the source or subject of discussion.
Ma lugesin Indrekust kirjutatud raamatut.
I read a book written about Indrek.
In this context, 'Indrek' is being used as a direct address to a person, capturing attention in a conversation.
Indrek, kas sul on aega rääkida?
Indrek, do you have time to talk?
The word 'Indrek' here is used as a proper noun, specifically a person's name.