The word 确凿 (quèzáo) is a compound formed by combining two characters with complementary meanings to create a vivid metaphorical sense of absolute certainty. The first character, 确 (què), means "solid", "true", or "reliable", establishing the core idea of firmness. The second, 凿 (záo), literally means "to chisel" or "an engraving tool", evoking the image of something being carved indelibly into stone or wood. Together, they create the powerful image of evidence or facts that are as undeniable and permanently fixed as if they were chiseled in stone, thus meaning "conclusive", "irrefutable", or "verified beyond doubt". This formation is a classic example of how Chinese compounds often use tangible, concrete imagery to express abstract qualities.