In this sense it means without (using) clothes.
Edit: You can see words including the Kanji here: http://jisho.org/words?jap=%E8%A3%B8&eng=&dict=edict It'll give you an idea of what the sense are (e.g. naked eye, just as in English, etc.)
In Danzan Ryu or Kodenkan Hawaiian Jujitsu NOT KODOKAN this is called Kate Gatame "shoulder hold" throw and hold with pressure on neck, arm across.I am responding to the first photo on this thread. Many will tap due to pain on the vagus nerve or glossopharyn-goal nerve, but we consider it a pin or hold down. We are taught you can not do a carotid choke without compressing both sides of neck This is the second technique on our third list called Shime. It is taught at green belt.
Yeh that's lovely, but its about 3 weeks late and doesn't even answer the OPs question.
You might have well as posted the gestation period of an African elephant.