What does icloud locked mean?

hello i need help buying a phone and this is the perfect price! Http://www.ebay.com/itm/Apple-iPhone-5-16GB-White-Sprint-Icloud-Locked-sold-as-is-/251389723565?pt=Cell_Phones&hash=item3a87fec3ad so I was wondering if there is anything wrong with it? Or what does icloud locked mean? Im not a big phone person and my older sister and brother get mad when I ask

It is locked to someones id. Cannot be restored without their password. Cannot be used. Stay away from it.

you can sear it in Google or you tube then you will find the all information there.

What does "locked in" mean?
How do I lock it in?