kum

1. (at a wedding) best man; wedding witness
   Moj najbolji drug će mi biti kum na venčanju. — My best friend will be my best man at the wedding.
   Kum je održao zdravicu za mladence. — The best man gave a toast to the newlyweds.
2. (at a baptism) godfather
   Kum je detetu na krštenju dao ime. — The godfather named the child at the baptism.
3. colloq. (as a form of address) close friend; buddy
   Kume, hajde na jedno piće! — Come on, buddy, let's grab a drink!
4. (reciprocal relationship) the father of one's godchild; the man whose best man or child's godfather one was
   Moj kum me je zvao na slavu — krstio sam mu sina. — My kum invited me to his slava — I'm his son's godfather.

In Serbia the wedding kum traditionally often also becomes godfather to the couple's children; the female form is kuma.