If you describe something such as furniture, clothing, or the way that a house is decorated as tasteless, you consider it to be vulgar and unattractive.
a house crammed with tasteless furniture.
一座塞满了毫无品位的家具的房子。
If you describe something such as a remark or joke as tasteless, you mean that it is offensive.
I think that is the most vulgar and tasteless remark I have ever heard in my life.
我认为那是我平生听到过的最庸俗最没品位的话。
If you describe food or drink as tasteless, you mean that it has very little or no flavour.
The fish was mushy and tasteless.
这条鱼烧得太烂了,而且没有味道。