sync itunes

ok, i have itunes from someone else on my ipod right now, and i want to add 1 app to what i currently have, is there any way I can do this without wiping clean what i already have? Like a hack for the sync on itunes?

I think I sort of understand what you're talking about, but really a LOT more clarification would be REALLY helpful, starting with all the models involved (Mac, PC, iTunes, iPod etc).

The short answer (if I understand your question) is no.

Thank you for understanding my question and not making fun of my ignorance

No problem. Fundamentally, an iDevice can only be synced to one iTunes account, so you have to pick which one and sync it.