simon-pure adj.

"genuine, pure, authentic, true," 1815, colloquial, from the true Simon Pure "the genuine person or thing" (1795), from the name of a Quaker character who is impersonated by another character (Colonel Feignwell) as part of the comedy "A Bold Stroke for a Wife" (1717) by English dramatist and actress Susannah Centlivre. In the play, the real Simon Pure is treated as an impostor and is believed only after he has proven his identity.