To Carve, To Cut Up
transitive verb, godan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means carve so the verb version is to carve.
きざむ
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: You don't have a knife for your steak, so you have to carve it using the key zag (きざ) technique. You take a key and zag it through the steak repeatedly until you're able to cut up some zaggy bite-sized pieces.
葱を刻むのは面倒くさいよ。
I can’t be bothered to cut up the green onion.