scrupulous

The word 'scrupulous' originates from the Latin scrupulus, a diminutive of scrupus, meaning a sharp stone or pebble. This literal sense evolved metaphorically to represent a troubling doubt or a pang of conscience, much like the discomfort caused by a small stone in one's shoe. In Roman times, a scrupulus was also a tiny unit of weight, reinforcing its association with minute and precise measurement. Thus, the modern abstract meaning, "characterized by a strict regard for what is right or proper," developed from the idea of being so sensitive to moral distinctions that one is troubled by even the smallest ethical 'pebble' or detail.

Structure: scrupul (a small sharp stone) + ous (adjective suffix) scrupul is from Latin scrupulus, meaning a small sharp stone or pebble, and by extension, a source of anxiety or doubt. ous is an English adjective-forming suffix from Latin -osus, meaning "full of" or "characterized by."