noun

a minor weakness or eccentricity in someone’s character.

they have to tolerate each other’s little foibles

weakness,weak point,weak spot,failing,shortcoming,flaw,imperfection,blemish,fault,defect,frailty,infirmity,inadequacy,limitation,quirk,kink,idiosyncrasy,eccentricity,peculiarity,abnormality,Achilles heel,chink in one’s armour,hang-up