This is the 980th most frequent Portuguese word.
boas
"Boas" means "good" (feminine plural) or is used as a casual greeting, "hi/hello."
In this sentence, 'boas' is an adjective describing the plural noun 'notícias', meaning 'good'.
Eu ouvi boas notícias ontem.
I heard good news yesterday.
Here, 'boas' is part of a set phrase meaning 'good afternoon', adjusted for plural cultural expression because 'tardes' is plural.
Boas tardes a todos!
Good afternoon to everyone!
In this example, 'boas' functions as an adjective modifying the feminine plural noun 'conquistas', also meaning 'good'.