taste neg in English:

Did you see that couple in matching outfits just now? How tasteless!

The last time I ate in that restaurant the food was completely tasteless. I think they must have forgotten to season it.

I think I’ll add some salt because the sauce is a bit tasteless.

tasteless soup

I'm afraid it's tasteless.

That outfit is really tasteless.

Foreign rice is hard and tasteless, and doesn't appeal to the Japanese palate.