depression, cave in, sink, become hollow
窪 centers on a sunken or hollowed-out space: a depression in the ground, a surface caving in, or something becoming hollow. The idea applies to physical dips and metaphorical sinking.
窪 combines 穴 (hole, cavity) with 洼, which likely contributes both sound and the idea of a hollow or depression. The structure suggests a hole that sinks or caves in.
The top 穴 is a hole, and the bottom 洼 looks like water (氵) over earth (土) with legs (儿) sinking in. Picture a water-filled hole in the ground where the earth is caving in, creating a depression.
For ワ, imagine a deep depression filling with water: water -> ワ, and the hole (穴) becomes a hollow pool.
hollow; cavity; sunken place
to cave in; to become depressed; to sink
downwarp
love is blind; (when in love) even pockmarks are dimples
hollow at nape of the neck
to cave in; to become depressed; to sink
hollow; low ground; basin; pit; dip; depression
hollow; pond in a hollow
to sink in; to cave in
Ochikubo Monogatari; The Tale of Ochikubo (Heian period Cinderella story)