The word "确凿" is formed by combining the character "确", which means certain or definite, with "凿", which means to chisel or carve. Individually, "确" contributes the sense of certainty, while "凿" implies something solidly established, akin to being carved into stone. Together, they form a compound meaning conclusive or irrefutable, typically used to describe evidence or facts that are firmly grounded and undeniable.