The word "千锤百炼" is formed by combining two parallel phrases, "千锤" meaning "thousand hammerings" and "百炼" meaning "hundred refinings", where each phrase consists of a numeral (千 for thousand, 百 for hundred) directly modifying a verb (锤 for hammering, 炼 for refining), creating a compound that literally denotes repeated physical forging and metaphorically conveys rigorous improvement or refinement through persistent effort.