tymczasowa moda in English:

Loose jackets are the latest fad.

this kind of tutoring is not just a passing fad

passing fad

The reason for this is that research is not a fad, but a necessity which guarantees the European economy's competitiveness at a global lev

managers' fad

How long you think this Internet fad is gonna last?

Cell phones are a popular new fad amongst teenagers these days

They were convinced that movies were only a passing fad.

There was a fad for wearing ripped jeans a few years ago.

The latest fad, though, is using the freeze-drying process on somewhat larger items: pets.