Paraphrasing is rendering of the meaning of some idiomatic phrase in the source language by a phrase in the target language consisting of non-correlated lexical units, e.g.
Good riddance - скатертью дорога; In for a penny, in for I pound - назвался груздём - полезай в кузов; взялся за гуж - не говори, что не дюж.
A phraseological unit is rendered by a corresponding Russian phraseological unit expressing the same idea in different words.