the word is a modern english compound formed by appending the native english adjectival suffix '-like' to the name of the mythological creature, the sphinx. the sphinx, originating in greek mythology (from a greek term possibly derived from a verb meaning 'to strangle'), was famously depicted with a human head and a lion's body and was known for posing a riddle. the core semantic link lies in the creature's iconic attribute of an inscrutable, silent, and mysterious presence. therefore, 'sphinx-like' does not refer to physical hybridity but metaphorically describes a person or expression that shares the sphinx's perceived qualities of enigmatic silence and impenetrable calm, transferring the mythological attribute to human behavior and appearance.

Structure: sphinx + like sphinx: from latin 'sphinx', from greek 'sphinx', meaning 'the strangler'. in this compound, it functions as the nominal root, referring to the mythological creature. like: from old english 'līc', meaning 'body, form; like, similar'. it functions as a suffix-forming adjective, meaning 'having the form or characteristics of'.