noun
backwards; back to front; inside out
Describes wearing something the wrong way round, such as a shirt with the front at the back, or putting something on backwards.
シャツを後ろ前に着てしまった。
I put my shirt on backwards.
帽子を後ろ前にかぶっているよ。
You're wearing your hat backwards.
Compound of 後ろ (ushiro, 'back') and 前 (mae, 'front'), literally 'back-front'.