In′ef‐fec″tu‐al (?; 135), a. Not producing the proper effect; without effect; inefficient; weak; useless; futile; unavailing; as, an ineffectual attempt; an ineffectual expedient. Pope.
The peony root has been much commended,... and yet has been by many found ineffectual. Boyle.
Syn. — Inefficient; useless; inefficacious; vain; fruitless; unavailing; futile. See Useless, Inefficacious.