What is a prefix for the Word tasteful?

There isn't a common prefix specifically for "tasteful". However, you can use prefixes to create related words with slightly different meanings:

* Un-tasteful: Meaning not tasteful, lacking good taste.

* Over-tasteful: Meaning excessively tasteful, perhaps to the point of being pretentious.

* Pre-tasteful: Meaning having good taste in advance, or showing good taste in advance of something.

You could also create more abstract prefixes, like:

* Hyper-tasteful: Meaning extremely tasteful.

* Neo-tasteful: Meaning having a modern or innovative sense of taste.

Ultimately, the best prefix to use will depend on the specific context and the desired meaning.