noun, na-adjective
Describes something being physically flipped so that top and bottom are reversed. Can also be used figuratively for a situation where the normal order is reversed.
絵が上下逆さまに掛けてある。
The picture is hung upside down.
上下逆さまの状態で箱を開けないでください。
Do not open the box when it is upside down.
Compound of 上下 (じょうげ, 'top and bottom') and 逆さま (さかさま, 'upside down, reverse').