errant
erring
error-prone
human
undependable
unreliable
weak
adulterated
blemished
careless
damaged
deceivable
defective
deficient
errable
erroneous
faulty
found wanting
heedless
immature
impaired
imperfect
imprecise
impure
inaccurate
inadequate
incomplete
inexact
lacking
liable to error
makeshift
mediocre
mixed
not perfect
off
open to error
partial
patchy
short
sketchy
undeveloped
uneven
unfinished
unperfected
unsound
unthorough
wanting
fail
fallacious
fallacy
fallibilism
fallibilist
fallibility
anæmic
changeable
defenceless
deprave
fickle
flawed
flighty
frail
infirm
mutable
overactive
perishable
prone
uncharitable
unfitted
unstable
untrustworthy
untruthful
weak-minded
infallible