the word 'thoroughness' is built upon the adjective 'thorough,' which originates from the old english word thurh, meaning "through." this spatial sense evolved metaphorically to describe an action performed from one end to the other, hence "complete" or "exhaustive." the suffix '-ness,' of germanic origin, is a highly productive morpheme used to form abstract nouns denoting a state or quality. therefore, the literal construction "the state of being through" logically developed into the modern abstract meaning denoting the quality of meticulous completeness and attention to detail.

Structure: thorough (complete) + ness (state or quality) - thorough: from old english thurh (through), functioning as the core adjective meaning "complete through and through." - ness: from old english -nes(s), a noun-forming suffix indicating a state, condition, or quality.