Antonyms for "art mark" could be "mistake," "failure," or "blemish." These words have negative connotations and imply a lack of skill or precision. Another antonym could be "plain," which suggests an absence of any artistic embellishment or skill. Conversely, antonyms for "art mark" could include "masterpiece," "perfection," or "genius." These words imply exceptional skill and talent, and are associated with high praise and admiration. Other possible antonyms could be "ordinary," "mediocre," or "average," which suggest a lack of extraordinary artistic ability or achievement.