impotent
incompetent
toothless
unproductive
abortive
aimless
barren
bootless
counterproductive
effete
emasculate
empty
etiolated
failed
failing
fatuitous
fatuous
featherweight
feckless
forceless
fruitless
futile
ill-qualified
inadequate
inane
incapable
incapable of
ineffectual
inefficacious
inefficient
inept
inferior
inoperative
invalid
invertebrate
lame
lightweight
maladjusted
manque
meaningless
miscarried
miscarrying
no go
no-account
not equal to
not up to
nugacious
nugatory
of no account
erroneous
impractical
inappropriate
pointless
unable
unimportant
uninteresting
unreliable
unsatisfactory
unwise
useless
vulnerable
affective
anti-infective
collective
connective
convective
corrective
defective
detective
directive
effective
elective
infective
introspective
invective
irrespective
objective
perspective
projective
prospective
protective
reflective
respective
retrospective
selective
subjective