
Is a colloquial way to call women who don't try to sugar coat their words.
In japan it is encouraged to mince and mind your words and try your absolute best to not be "rude" or "impolite" to others, so much so that there is a formal and informal way to speak and pronounce words.
The "Saba Saba" term is for the people who disregard the idea of ""saying things in a round about way is what being polite means"" instead opting for straightforwardness.
I belive the manga tries to portray both the people who actually are straightforward with their views and beliefs and those who use "blunt" as an excuse to insult, diminish and manipulate.
Looking through the comments and I think I already hate it (/TДT)/ I thought it could be a wholesome friendship that's what i thought when i read the bio like in Thailand tgeres this saying "Saba Saba" or "sabai sabai" which means comfortable comfortable / relax relax so I thought the"real" saba Saba girl would teach mc to be comfortable in her own skin ╥﹏╥