Clear can be transitive or intransitive. It can be followed by the prepositions away, off, out or up. When followed by these prepositions  it can be either “transitive” or “intransitive”.

Prasal verb Translation Examples
Clear away (transitive) spostare, togliere He cleared all the books away from the table to make more room to work.
Clear away (intransitive) disperdersi At 9 the fog was very thick but around 11 it cleared away.
Clear off (intransitive) Andare via, alzare i tacchi “Clear off” the policeman told the man who was annoying an old lady.
Clear off (intransitive) Andare via, alzare i tacchi  The farmer told the visitor to clear off from his fields.
Clear out (intransitive) Andare via, alzare i tacchi “Clear out” shouted the guardian to the boys playing football in the park.
Clear out (transitive)  Svuotare  I had to clear out most of my wardrobe to make room for her clothes.
Clear up (intransitive)  Aprirsi It was ovecast in the early morning but it cleared up towards midday.
Clear up (intr. or trans.)  Ordinare, ripulire  The room was a real mess. I had to clear it up.
Clear up (transitive) terminare I want to clear up the report before leaving.
Clear up (transitive) risolvere Against all expectations he managed to clear up the mystery.