the word spurious has a direct lineage from the latin adjective 'spurius', which originally meant 'illegitimate' in reference to a child. this latin term is thought to be of etruscan origin, though its ultimate roots are obscure. the core concept of falseness or illegitimacy was retained as the word entered english in the late 16th century. over time, its application broadened from describing illegitimate birth to characterizing anything that is not authentic, genuine, or logically valid, thus connecting the ancient notion of falsity to modern abstract and concrete deceptions.

Structure: spur (false) + ious (adjective-forming suffix) 'spur' originates from the latin word 'spurius', meaning illegitimate, false. the suffix '-ious' is a latin-derived adjectival suffix meaning 'characterized by, full of'.