ineffectual
adj
lacking confidence and unable to get things done; without effect 信心不足而又無能為力的; 無效的; 不起作用的
make ineffectual attempts to do sth 徒然嘗試做某事
ineffectual as a leader, teacher, etc 作領袖、 作教師等不能勝任的
a well-meaning but ineffectual person 心有余而力不足的人.