烈

ardent, violent, vehement, furious, severe, extreme

Kun

はげしいhageshii

On

レツretsu

Kun is the Japanese reading, used when the kanji stands alone with kana after it. On comes from Chinese and is mostly used in compound words.

Radical

火fire

Parts

灬fireform of 火刂knifeform of 刀歹death