genuineness or spuriousness; authenticity; the genuine and the spurious
imitation; fake; phony; pseudo-
spurious article; forgery; counterfeit; imitation; sham
counterfeiting; forgery; fabrication
impostor; imposter; pretender; liar
counterfeiter; faker; appropriationist
argument as to (about) the authenticity (of...)
black locust; robinia pseudoacacia