the edible water-frog
鼃 refers specifically to an edible water frog. It is a rare, specialized character with no broader conceptual center beyond this single meaning.
鼃 combines 圭 (top) and 黽 (bottom, a pictograph of a frog or toad). The character likely uses 黽 as a semantic indicator for a frog-like creature, while 圭 may have contributed a phonetic element, though the exact historical development is uncertain.
The bottom component 黽 looks like a stylized frog with a broad head and legs. The top 圭 resembles piled earth. Picture a frog sitting on a mound of earth by the water's edge—this is the edible water frog.
For ワイ, imagine asking 'Why?' (ワイ) is this frog edible? The sound 'why' cues ワイ while you look at the strange frog character.