curtain off
To use a curtain to prevent access to a particular area or thing. A noun or pronoun can be used between "curtain" and "off." We had to curtain off that section of the restaurant for a private party.
curtain something off
to separate something or some place with a drape, screen, or curtain. We curtained this part of the room off, so please sleep over there. We will curtain off part of the room.