Powerless
Powerlessness, Helplessness
noun, な adjective, の adjective
When your power is nothing you are powerless.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. You also can know that 力 uses its りょく reading because when you tried to pick up a tiny rock (りょく) you couldn't, because you were powerless.
自分がどれだけちっぽけで無力な存ざいであるかを思い知らされました。
That made me realize how tiny and powerless I am.
「無力の証明」というゆうぎ王カードを手に入れました。
I got a Yu-Gi-Oh! trading card called "Proof of Powerlessness."
警察はそのストーカーに対して無力で何をすることもできず、結局彼女は殺されてしまった。
The police were powerless to do anything about the stalker and in the end she was killed.