Sponginess is the quality of being spongy — soft, full of tiny air holes, and springing back a little when you press it. It is the noun for a feeling in your hand or your foot. Fresh bread has it, a good cake has it, wet ground after rain has it, and so does a mattress that gives way under you. Two things live inside the word: softness, and the small bounce that comes from air trapped in holes. That second part is why sponginess is not the same as plain softness — butter is soft but not spongy, because it does not push back. Whether it is a good thing or a bad thing depends entirely on what you are touching. A baker wants sponginess in a cake and will praise it. A driver does not want sponginess in the brake pedal, and a doctor does not want to feel sponginess where a bone should be firm — there it is a warning. So the word itself is neutral; the situation decides. It is not a common everyday word. You meet it in cooking writing, in descriptions of soil and ground, and in technical talk about materials.

鬆軟有彈性的質地、海綿感；講蛋糕麵包時是「鬆軟度」，講土地是「軟綿綿、踩下去會陷」，講煞車踏板則是「軟軟的（不對勁）」