From answers.com: The condition or state of being incapable of accomplishing or effecting anything: helplessness, impotence, incapability, ineffectiveness, ineffectuality, ineffectualness, inefficacy, powerlessness, uselessness. See affect/ineffectiveness, strong/weak.
The condition or fact of being deficient: defect, deficiency, deficit, insufficiency, lack, paucity, poverty, scantiness, scantness, scarceness, scarcity, shortage, shortcoming, shortfall, underage1. See excess/insufficiency/enough.