pungent, spicy, harsh, cruel, severe
辣 centers on a sharp, intense quality that can be physical (pungent, spicy) or figurative (harsh, cruel, severe). The idea is something that stings or bites, whether on the tongue or in behavior.
辣 combines 辛 (spicy, bitter) with 束, which likely contributes a phonetic element. The character expresses the idea of sharp, pungent taste or harshness.
On the left, 辛 (spicy, bitter) already suggests a sharp taste. On the right, 束 (bundle) looks like a tied bunch of hot peppers. Together, they make 辣: a bundle of spicy, pungent heat.
For ラツ, imagine a rat (ラット) that ate something so spicy it starts running in circles: rat -> ラツ, and the spicy 辣 makes it go wild.
bitter (e.g. criticism); sharp; biting; severe; scathing; harsh
mala (spicy and numbing seasoning)
crafty; vicious; unscrupulous; sharp
Chinese onion (Allium chinense); Chinese scallion; Kiangsi scallion; rakkyo
shrewdness; sharpness; astuteness; acumen; tact
Japanese onion (Allium thunbergii)
laziji; spicy Sichuan chicken dish
hot-and-sour cabbage
hot and sour soup
hot and sour noodles (Szechuan dish)
malatang (Sichuan-style spicy street food)