ステテコ

noun

long men's underpants; loose Bermuda-style underpants

A type of men's underwear resembling loose, knee-length shorts, often worn under trousers. Considered old-fashioned by younger generations but still used for comfort or as loungewear.

• 夏なつはステテコで過すごすのが涼すずしくて好すきだ。

  In summer, I like spending time in step-in underpants because it's cool.

• 祖そ父ふはいつもステテコをはいている。

  My grandfather always wears long underpants.