zakazivati

1. to schedule; to arrange; to book
   Termine kod zubara zakazujem preko telefona. — I book dentist appointments by phone.
   Šef stalno zakazuje sastanke u petak popodne. — The boss keeps scheduling meetings on Friday afternoons.
2. (of a machine, organ) to fail; to malfunction
   Kočnice su počele da zakazuju na nizbrdici. — The brakes started failing on the downhill.
   Pamćenje mi sve češće zakazuje. — My memory fails me more and more often.
3. (of people, institutions) to fail; to let down
   Institucije zakazuju kad je najpotrebnije. — Institutions fail when they're needed most.

The perfective is zakazati; colloquially zakazati kod lekara means "to make a doctor's appointment".