* Unfashionable: This means not fashionable, out of style.
* Pre-fashionable: This means something that was fashionable in the past but is not anymore.
* Anti-fashionable: This means something that is deliberately against fashion trends.
* Super-fashionable: This means extremely fashionable, highly stylish.
* Hyper-fashionable: This means excessively fashionable, almost to the point of being over-the-top.
The best prefix to use will depend on the specific context and the nuance you want to express.