de feasible (adjective) ineffective/ineffectual: weak, useless
Sinonime: abortive, anticlimactic,
barren, bootless, defeasible,
feckless,
feeble, forceless,
fruitless,
futile,
idle,
impotent,
inadequate,
incompetent,
indecisive, inefficacious,
inefficient,
inept,
inferior,
innocuous, inoperative, invertebrate,
lame,
limited, neutralized,
nugatory,
null, null and void,
paltry,
powerless, spineless,
unable, unavailing, unfruitful, unproductive, unprofitable,
unsuccessful,
vain,
void, withered,
worthlessAntonime: competent,
effective,
effectual,
efficient,
powerful,
strong,
useful