KanjiJLPT N1
Spicy / Biting

pungent, spicy, harsh, cruel, severe

Mnemonic

You open a bundle of dried spicy peppers. The instant you do, a wave of spicy, biting heat hits your nose so hard your eyes water and you can't breathe. That bundle was pure, merciless fire.
Additional thoughts
Imagine ripping open a tied bundle of ghost peppers—the spicy dust cloud hits your face and the biting sensation is inescapable. The radical 'spicy' provides the flavor; 'bundle' is the package holding it all in.
Quick recall
Ripping open a bundle of spicy peppers unleashes spicy, biting fury.

Details

The keyword for 辣 is spicy / biting. This kanji refers to a sharp, pungent, or hot flavor, particularly the kind of intense heat associated with chili peppers or strong spices. Beyond the literal taste sensation, it also carries a figurative meaning of being harsh, ruthless, or cutting, as in a biting remark or a merciless action. This dual sense of physical spiciness and metaphorical severity gives the character a broad range of use in describing anything intensely sharp or unsparing.
On'yomi
らつ
Kun'yomi
から.い