I often see items' condition described as "junk".
Does that mean its not working, and only good for parts or repair, or is it a short-cut way of saying "used and kinda beat up"?
They usually clarify the reason in the description;
It might not be working at all - doesn't power up
It might have an issue - one channel doesn't work
It might be in poor cosmetic condition
The seller may not be able to check all the functions
The seller might not have the equipment necessary to check that it functions at all
Basically treating something as "junk" means there is no warranty for anything and the buyer agrees to make no claim, in English it's probably close to "as-is".
You can get bargains when buying "junk", like when the reason for junk treatment is "gari" and you know you can just clean the pots and it will probably be good as new, or because it's a little beat up and you don't care about the cosmetics.
And example (no affiliation);
http://page13.auctions.yahoo.co.jp/jp/auction/r126583141
☆店舗買取品です。
☆通電OK。
☆warm up ランプが点滅したまま使えないのでジャンク品での出品です。
☆現状で販売いたします。
☆修理や部品取りでお使いください。
Powers up OK
The warm up light doesn't stop flashing so it can't be used as-is
Will be sold as-is
Buyer needs to repair it or use it for parts