Noun
こぶし
彼は拳についた血をハンカチで拭いました。
He cleaned the blood off his fist with his handkerchief.
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you to remember: You make a fist. Why? Because she stole your corn on the cob. "Cob! She (こぶし) stole my cob!"