The antonym for "over laying" is "underlying". While "over laying" means to place something on top of another, "underlying" means to be beneath the surface or the basic foundation of something. The concept of underlying is often used in finance, where it refers to the fundamental value or potential of an asset, while overlying refers to a temporary situation or a superficial layer. In biology and geology, underlying refers to the substrate or the rock beneath the soil, while overlying refers to the vegetation or the sediment on top of it. Understanding antonyms like underlying and overlying can help us better comprehend the nature of the things around us.