1590s, "born out of wedlock," from Latin spurius "illegitimate, false" (cf. Italian spurio, Spanish espurio), from spurius (n.) "illegitimate child," probably from Etruscan spural "public." Sense of "having an irregular origin, not properly constituted" is from c.1600; that of "false, sham" is from 1610s.
spurious spu·ri·ous (spyur'ē-əs)
Similar in appearance or symptoms but unrelated in morphology or pathology; false.