Close up and Keep down

Close up verb - Unite or bring into contact or bring together the edges of.

Keep down and close up are semantically related In some cases you can use "Keep down" instead a verb "Close up".

Keep down verb - Place a limit on the number of.

Close up and keep down are semantically related in silence topic. Sometimes you can use "Close up" instead a verb "Keep down", if it concerns topics such as make or be quiet.