buff up

1. (идиома, переходный)To improve.

2. (переходный)To shine; to make shiny.

3. (идиома, непереходный)To become more muscular.

4. (идиома, непереходный)To study hard to learn a particular subject.

   I'll need to buff up on my Italian before my trip to Genoa.

неправильный

• buff outполировать, заполироватьTo remove paint or light scratches from the surface by friction, wearing it out by polishing or blasting with sand or by employing some similar method.
• buff upTo improve.
• buff downTo make (a surface) smooth by buffing.