Oi

Oh is the italian equivalent of hey (since we don’t use hey that much) and a lot more. Depending on the context/tone of voice it can mean different things: it’s used as a very informal greeting or as a way to answer the phone (again, only with someone you have great confidence with), but also, if said very loudly and with a lot of ‘o’,(=oooh) as a way to express frustration/impatience. Some people manages to use it in his aggresive acception even with one single ‘o’ before the ‘h’.   

If you happen to be roman and in need to be really, really aggressive, like Giovanni Garau when he confronts homophobic assholes or classmates that laugh at his best friend for being gay, then you’ll probably add an ‘a’ before the ‘ò’. When the ‘a’ is there too there’s no mistaking the meaning, a roman is going to fight you. Aò. (Only case when there’s no h)

If you’re blonde and hot like Filippo Sava, you’ll find yourself singing ooooh oooooh as the song Rap Futuristico asks you to (managing to annoy your sister who is trying to study and text with her crush).