Origin of admixback-formation , by analogy with mix from admixt, mixed with from Classical Latin admixtus: see admixture
tr. & intr.v.ad·mixed, ad·mix·ing, ad·mix·es
Origin of admixBack-formation from obsolete admixt mixed into from Middle English from Latin admixtus past participle of admiscēre to mix into ad- ad- miscēre to mix ; see meik- in Indo-European roots.
(third-person singular simple present admixes, present participle admixing, simple past and past participle admixed)
ad- + mix