bolovati

1. (+ od + gen.) to be ill; to suffer from
   Moj deda već godinama boluje od dijabetesa. — My grandfather has been suffering from diabetes for years.
   Bolovala je dugo, ali se oporavila. — She was ill for a long time, but she recovered.
2. colloq. (of work) to be on sick leave
   Kolega boluje već dve nedelje. — My colleague has been on sick leave for two weeks.
3. (+ za + instr.) to pine for; to long for
   Još uvek boluje za njom. — He still pines for her.
   Godinama je bolovao za rodnim krajem. — For years he pined for his home region.

The illness is introduced with "od" + genitive: bolovati od gripa. Pining for someone or something takes "za" + instrumental: bolovati za nekim.