noun

a fault, blemish, or undesirable feature.

the imperfections and injustices in our political system

defect,fault,flaw,deformity,discoloration,disfigurement,crack,break,scratch,chip,dent,pit,notch,nick,blemish,stain,spot,mark,streak,failing,deficiency,weakness,weak point,weak spot,shortcoming,fallibility,frailty,infirmity,foible,inadequacy,limitation,Achilles heel,chink in one’s armour,hang-up