E.g. in English and Japanese (下着)it means "clothes worn under other clothes" or "lower clothes". In Russian (бельё) and Ukrainiian (білизна) it is "white things", which may seem to sound paradoxal in "black underwear" (lit. "black white things") :) Although they may also be called "нижнее бельё/нижня білизна" ("lower white things") to distinguish them from bedding that also goes by that name.
Other languages?