Hi Alina, Great question. When we speak about fabrics, the term we use is "sheer". A sheer dress, a sheer blouse, a sheer cover-up, etc. However, if someone thinks this is shocking and they want to emphasize that they can see right through the fabric, they may use the term "see-through" because they don't think this is a good thing. "The dress was completely see-through! That's not appropriate to wear to a funeral!" I hope that helps.

They are synonyms, though "see-through" is said by children and less-intelligent people. However, I suspect that you don't mean transparent (like glass). In the case of fabric, we use an idiomatic word "a sheer dress", which means translucent or semi-transparent.