Most often expanded into the four-syllable
赤身裸体 (chìshēn luǒtǐ, stark naked) for emphasis. The
赤 here keeps its old meaning of 'bare, empty' — same root as
赤手空拳 (chìshǒu kōngquán, bare-handed) and
赤贫 (chìpín, dirt poor). The literal 'red' meaning of
赤 is a separate sense.
