false; fake; invented

a spurious excuse

said of argument or reasoning: apparently sound but containing flaws

said of a material, biological part, etc: not the thing in question though superficially resembling it

German miners found a spurious copper ore which they called Kupfernickel, or ‘copper devil’

archaic said of a child: illegitimate

adultery by the wife followed by the birth of a spurious child — Law Report, Queen's Bench Division, 1885