HAIKYUU HEADCANONS!!

Swearing, Cursing

-Satori Tendou

Tendou probably cannot control his mouth. He's the type to bump into a table and even if it doesn't hurt, his word options are 'ow' or 'fuck' under his breath. When he curses it's really funny though so you can let it slide. I feel like when he's more serious or upset, he curses less. Semi has probably told him to watch his mouth.

-Koushi Sugawara

I feel like Suga isn't aggressively cursing. He definitely curses more when he's joking around but besides that he doesn't need to watch his mouth because he isn't thinking about using a curse in a sentence. He def curses under his breath especially when around people he doesn't like. "Asshole.." you'd look at him like ?? and see that he's grumbling under his breath about something so you're like "Koushi, control yourself."

-Rintarou Suna

Doesn't curse aggressively but it definitely comes natural. Atsumu would challenge him to control his mouth for a day and he'd definitely fail just because it's in his daily vocabulary. He does it so casually too that you don't realize that he swears everyday.

-Kenma Kozume

Aggressive and natural. He doesn't do it much in public. I feel like he's definitely mumbled "shut the fuck up" loud enough for Lev to hear though. The aggressive is for when he's gaming at 3 am. All you can hear from is room is him calling someone a dumb ass and telling people to stfu. 

-Shoyo Hinata

Hinata doesn't curse, he's a shy uwu baby guys.

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Im kidding wtf. Hinata definitely curses but it's always at the wrong time. Like you'll find him making a joke in school and suddenly there's a teacher behind him. Or situations like when he told Ushijima he was gonna kick his ass knowing damn well Ushijima is 5+ inches taller than him. Hinata could go a day without cursing though, nothing serious.

-Nishinoya + Tanaka

Do i even need to say much? Have definitely gotten in trouble in school together for that reason way too many times. It's mostly for fun and jokes, nothing serious like black air force energy unless they're trying to rile up another team and Daichi has to go ahead and put them on a leash.

-Kei Tsukishima

Does it deliberately. He chooses when he wants to and when he doesn't want to. He's not gonna do it in casual convos but as soon as he wants to piss someone off, he's all for it. He knows what's too much and what isn't, when to curse and when not to.

-Osamu Miya

Pretty sure it's canon that Osamu is trying to curse less. Like he tries to control his mouth and keep a calm demeanor but people like Atsumu really know how to get him to cuss up a storm. When it comes to Atsumu, he has no problem with telling him to stfu and calling him an asshole and shit like that but around everyone else, he rarely curses. He does it more in his head though and when he's by himself.