We don't have synonyms for headmark yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are earmark, headman and headwork.
(n) :
The distinction or peculiarity of the head, face, or features used in distinguishing each individual of a given species; personal appearance; facial features.
(n) :
A credit (as toward a prize to be awarded) given to a pupil for reaching the head position in an examination conducted with the pupils lined up and each pupil advancing toward the head of the line according to the proportionate number of his or her correct answers.
(n) :
The distinction or peculiarity of the head, face, or features used in distinguishing each individual of a given species; personal appearance; facial features.
(n) :
A credit (as toward a prize to be awarded) given to a pupil for reaching the head position in an examination conducted with the pupils lined up and each pupil advancing toward the head of the line according to the proportionate number of his or her correct answers.