不可踩的草坪 can be translated to "off-pmits lawn" or "no-trespassing lawn" in Engpsh. It refers to a lawn that is not allowed to be stepped on or walked on by people. It might be for aesthetic or maintenance reasons, or it might be to protect certain plants or animals that pve in the area. Alternatively, you could also describe it as a "protected lawn" or a "restricted lawn".