zaključiti

1. to conclude
   Iz njegovog ćutanja zaključila sam da se ljuti. — From his silence I concluded he was angry.
   Lekar je zaključio da nije ništa ozbiljno. — The doctor concluded it was nothing serious.
2. (of a contract, deal) to conclude; to sign
   Dve firme su zaključile ugovor o saradnji. — The two companies signed a cooperation agreement.
3. (of a meeting, speech) to close; to conclude
   Predsednik je zaključio sednicu u podne. — The chairman closed the session at noon.
   Zaključila je govor pričom o svojoj baki. — She concluded her speech with a story about her grandmother.
4. (in school) to give a final grade
   Profesorka mi je zaključila peticu iz matematike. — The teacher gave me a top final grade in maths.

Don't confuse it with zaključati, 'to lock'.