A grim, enduring grit.
A grim, enduring grit — the will to press on past the point where one's strength seems spent, especially when the odds look hopeless. Finns hold it up as a defining trait of their national character.
Sustained, against-the-odds resolve rather than a momentary brave act — and, researchers stress, better described as a reserve of latent power tapped in acute, overwhelming moments than as the long-term goal-perseverance of “grit.” It adds a stoic, almost anatomical “from the guts” connotation, and can be negative in excess: Finnish pahansisuinen (“bad-sisu'd”) means hostile, and excess sisu shades into bull-headedness.
From sisus “interior, insides, guts.”
From Finnish sisus “interior, insides, guts.” The word predates the modern Finnish state, appearing in written records for centuries.
A long-standing concept popularized as national-character shorthand around the 1912 Olympics and during the Winter War (1939–40); since c. 2013 it has been operationalized in positive-psychology research (the “Sisu Scale,” distinguishing beneficial from harmful sisu).
Often oversimplified in English as mere “grit” or “guts”; researchers stress it denotes a short-burst reserve of extraordinary power in acute adversity, and is not exclusively positive (excess → inflexibility, foolhardiness).