'não' means 'no/not/don't/doesn't' , in portuguese there's no auxiliar verb for negative sentences , so we use always the same word 'não'
Ele não gosta de sorvete (He doesn't like icecream)
Ela não é professora (She's not a teacher)
Não! Não faça isso! (No! Don't do this)
Actually, it's common to hear people pronouncing 'não'(naang-oo) as 'num'(noong) when it's before a verb (it's informal way)
Ela num é professora (She's not a teacher)
'Não' and 'num' are correct in speaking, although we write always 'não'(formal way)
'num' is only used in informal speaking and in some dialects there's no difference between these words) i hope u got it!
