Which word best correlates with "blemish"?

The word that best correlates with "blemish" is "defect." A blemish is essentially an imperfection or mark that damages the appearance or quality of something. In this context, both "blemish" and "defect" refer to something that detracts from the ideal state of an object, suggesting a flaw or imperfection.

While "mark" might seem related, it does not inherently carry the connotation of a negative imperfection; marks can be neutral or even decorative. Similarly, "perfection" and "flawless" are antonyms to "blemish," as they imply an absence of flaws or defects entirely, which contrasts with the idea of a blemish as something that exists as an imperfection. Thus, "defect" is the term that captures the essence of a blemish by indicating something that reduces the quality or integrity of an object.