The Chinese word **沉没** is a compound verb formed through the combination of two near-synonymous characters: **沉** (chén), which means "to sink, to submerge, or to be heavy," and **没** (mò), which means "to submerge, to disappear beneath, or to be engulfed." Together, they form a complementary or coordinative compound (联合式合成词) where each character reinforces and specifies the other's meaning, creating a more complete and vivid concept of "to sink and disappear underwater," i.e., "to sink" or "to submerge" entirely, often used for ships or objects going beneath the surface of water.