noun
backless (women's clothing)
Used in fashion contexts for dresses or tops that expose the back.
彼女はパーティーにベアバックのドレスを着て行った。
She went to the party wearing a backless dress.
noun
bareback riding
Refers to riding a horse without a saddle; less common than the fashion sense.
彼はベアバックで馬に乗るのが好きだ。
He likes riding a horse bareback.