bad habit
besetting sin
blemish
bug
catch
crack
crotchet
defect
defection
deficiency
drawback
eccentricity
failing
failure
fault
faute
feeble
flaw
frailty
hang-up
hole
idiosyncrasy
imperfection
inadequacy
infirmity
kink
little problem
moral flaw
peculiarity
preoccupation
problem
quirk
rift
shortcoming
snag
something missing
taint
vice
vulnerable place
weak
weak link
weak point
weak side
weakness
distinctiveness
part
portion
speciality
specialness
specialty
absurdities
blunder
corruptions
deformity
excellences
imprudence
incongruity
inconsistency
irregularities
oddity
thoughtlessness
whim