foible (n.)

• blemish
• bug
• catch
• crack
• crotchet
• defect
• defection
• deficiency
• drawback
• eccentricity
• failing
• failure
• fault
• flaw
• frailty
• hang-up
• hole
• idiosyncrasy
• imperfection
• inadequacy
• infirmity
• kink
• peculiarity
• preoccupation
• problem
• quirk
• rift
• shortcoming
• snag
• taint
• vice
• weakness