Sisu is when you sit in sauna longer than your neighbor... Sisu is when you score goal on the last seconds of the match... Sisu is what allows you to survive a finnish winter... Taking shot of vodka without even a single move of your face muscles is sisu.
Endurance? Patience? Stamina? I don't know... It's somewhere on between, but for sure it's a deeply Finnish thing :)
i'm sure some people will agree with you, but on the other hand, learning languages is a lot to do with learning the cultures they are spoken in, and we come to the discussion and someone explains to their best ability so you learn more than what the course officially offers to teach us. i think it's cool.
Sisu is courage or bravery (sort of) - the noun for the chacter trait or the idea. You would say "a courageous man/a man with courage", or "a brave man/a man with bravery", not "a courage man" or "a bravery man", so you have to say " a man with sisu". Never actually heard "a man with bravery" but it meets the rules of English and could possibly be used.