Originally ideogrammic compound (會意) and phono-semantic compound (形聲, OC *smaːŋs, *smaːŋ): phonetic 桑(OC *sŋaːŋ, “mulberry tree”) + semantic 㗊(“many mouths”). The number of mouths frequently varied. Sometimes 走 (“run”) was included as a semantic component, and later 亡 (OC *maŋ, “die”) was added as a phonetic (and also possibly semantic) component.
In the seal script became ideogrammic compound (會意) and phono-semantic compound (形聲, OC *smaːŋs, *smaːŋ): semantic 哭(“cry”) + phonetic 亡(OC *maŋ, “die”), from which the modern form derives.
Compare 咢 and 噩, which may be derived from or originally the same character as 喪.
From Proto-Sino-Tibetan*ma(“not”). Cognate with 亡 (OC *maŋ, “to disappear”). The level-toned pronunciation has a nominal prefix *s-, lit. "circumstances associated with disappearance (death)", whereas the departing-toned pronunciation has a formally identical causative prefix *s- and an exoactive suffix *-s, lit. "to cause to disappear".