ineffectual
adj
lacking confidence and unable to get things done; without effect 信心不足而又无能为力的; 无效的; 不起作用的
make ineffectual attempts to do sth 徒然尝试做某事
ineffectual as a leader, teacher, etc 作领袖、 作教师等不能胜任的
a well-meaning but ineffectual person 心有余而力不足的人.