humble, deccan grass
稗 centers on a lowly, humble status, like a common weed or grass. The deccan grass meaning is a specific plant, but the core idea is something considered insignificant or base.
稗 combines 禾 (grain/plant) with 卑, which likely contributes both sound and the idea of lowliness, suggesting a humble grass or weed.
The grain plant 禾 next to 卑 (base, lowly) gives a humble grass: deccan grass, a weed-like plant considered insignificant.
For ハイ, imagine a humble farmer saying 'Hi' to the deccan grass: Hi -> ハイ, as he greets the lowly weed in his field.
barnyard millet (Echinochloa esculenta); Japanese millet; sanwa millet
pearl millet (Pennisetum glaucum)
finger millet (Eleusine coracana)
people's history (written for the king of China; usu. written as a novel)
petty official responsible for collecting public gossip and presenting it to the king (in ancient China)
Kodo millet (Paspalum scrobiculatum)
Japanese paspalum (Paspalum thunbergii)