From sisä-, meaning inner or interior — it first meant a person's physical insides, then their core, then their courage. The same road English "guts" travelled. In Finnish texts since the 16th century.
literally: inner stuff
What it means
Not grit and not resilience — resilience is recovering, grit is pushing toward something. Sisu is continuing when continuing is no longer reasonable, quietly, without spectacle. It is usually only named afterwards.
pahansisuinen — "bad sisu" — means a hostile person. Excess sisu becomes bull-headedness. Finnish itself admits too much goes bad.最近的汉语
韧劲，是接近的，但太中性了。骨气又带着一种道德上的傲气，sisu 没有这个意思。
我想，这个词里有种东西，汉语没有单独给它命名——不是因为我们不知道那种感觉，而是因为我们习惯把它藏在别的词里，或者根本不说出来。
也许正因如此，它只能在事后被叫出名字。
Shadow