simon-pure
Concise Oxford English Dictionary © 2008 Oxford University Press:
simon-pure/sʌɪmənˈpjʊə/
▶adjective completely genuine or honest.
– origin C18: from (the real) Simon Pure, a character in Centlivre's A Bold Stroke for a Wife (1717), who for part of the play is impersonated by another character.
'simon-pure' also found in these Oxford entries:

