Tacksville means extremely tacky, so tacky you just don't know what to do, laugh or cry.
Do you like Yvette's dress with the zebra print and bright green flower bra over the top?
That dress is so tacksville. I don't know how a designer was able to create it and a store was able to stock it.
Another way of saying something is very tacky.
That dress Candela's got on? Totally tacksville.