I've searched on the web and haven't found a meaning for it, Most websites assume it is a German word. I saw it on the phrase:
Eine ego ut adverser?
This phrase is from an example in the book "Gramática Latina Napoleão Mendes de Almeida" page 395, paragraph 423. The paragraph talks about questions constructed with the future perfect and gives this as an example.
I could not find the verb whose future perfect in Latin is "eine" in the web and adverser is on the present, subjunctive and passive.