The verb "hiányzik" can mean to miss someone or something, for exemple: I miss my dog. I miss my brother. I miss the old days. I miss my job. But you can also use it if something is missing "in the space". For exemple: Its top is missing. One letter is missing from this phrase. The end of it is missing. One of the lenses is missing. He is missing from the classes. So basically you can use it to express your emotions that you miss someone or something, and you can use it as saying that something is missing "in the space" (there isn't something). I think that's it on when you use it. So the stem of the verb is "hiány",( wich is kind of like a noun form of the verb to miss, so like the to miss is a fact that something is missing but "hiány" is like "the miss" itself as a noun. I don't think sot that there is such a word in English but I hope you get it),so when you conjugate the verb you just cut out the"-zik" part from "hiányzik", and you add the different endings: Én hiányZOM (or ZOK,that's your guess, both are correct) neki/valakinek/valahonnan.. -> He/she miss me/Somebody miss me/I'm missing from (school) Te hiányZOL neki/ valakinek/ valahonnan..-> He/she miss you/Somebody miss you/ You're missing from (school) Ő hiányZIK (here you use the original form) neki/valakinek/valahonnan..-> He/she miss him/her (in Hungarian there is no he, she, him,her, just "ő" wich is basically used for both boys and girls) , Somebody miss him/her...and He/she is missing from (school). Mi hiányZUNK neki/valakinek/valahonnan..-> He/she miss us / Somebody miss us / We're missing from (school) Ti hiányOZTOK neki/valakinek/valahonnan..-> He/she miss you /Somebody miss you/You're missing from (school) Ők hiányOZNAK neki/valakinek/valahonnan..-> He/she miss them/Somebody miss them/They're missing from (school) ...And if you wanna say that It is missing, you just say: Hiányzik. (in ungarian you don't say that "it" in this case if you don't say the name of what is missing) Hope it helped!

The infinitive is "hiányozni".