noun

1. a quality deserving blame; fault; defect
2. lack of merit
3. ☆ a mark recorded against a student, trainee, etc. for poor conduct or work

Etymology: ME & OFr demerite < ML demeritum, fault < pp. of demerere, to forfeit, not merit, with meaning altered (de- taken in negative sense) < L, to merit < de-, intens. + merere, to deserve