/ diːˈmerɪt; NAmE / noun ( formal )
1.
[ usually pl. ] a fault in sth or a disadvantage of sth :
the merits and demerits of the scheme
2.
( NAmE ) a mark on sb's school record showing that they have done sth wrong :
You'll get three demerits if you're caught smoking on school grounds.
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WORD ORIGIN
late Middle English (also in the sense merit ): from Old French desmerite or Latin demeritum something deserved, neuter past participle of demereri , from de- thoroughly (also understood in medieval Latin as denoting reversal) + mereri to merit.