If you are helpless, you do not have the strength or power to do anything useful or to control or protect yourself.
例句
Parents often feel helpless, knowing that all the cuddles in the world won't stop the tears...父母經常感到無能為力，因為他們知道無論多少次擁抱也無法止住眼淚。Children are dying, and I am helpless to do anything...孩子們已奄奄一息，而我卻無力做任何事情。
英漢詞典釋義
adj.
無助的, 無保護的
They felt helpless to do anything about it.他們對這事感到無能為力。