cutting (grass)
苅 centers on cutting grass or vegetation, with a specific focus on mowing or trimming plants.
苅 combines 艹 (grass) with 刈 (cut, mow), forming a compound ideograph for cutting grass. The exact historical development is uncertain, but the component relationship is clear.
Grass 艹 on top of a cutting tool 刈: picture a scythe slicing through tall grass, trimming it down.
For ガイ, imagine a guy mowing the lawn: guy -> ガイ, and he's cutting the grass.