Mar·cion·ism 
(märshə-nĭz′əm)
(märshə-nĭz′əm)n.
A Christian heresy of the second and third centuries AD that rejected the Old Testament and denied the incarnation of God in Jesus as a human.
[After Marcion (died c. AD 160), Pontic merchant and heretic in Rome.]
Marcion·ite′ (-shə-nīt′) n.