• having your state vanish out from under you, (usually in combination with an inability or unwillingness to adopt the nationality of the successor regime) as in the case of, say, Palestinian refugees.
• renouncing your nationality (expatriation) if such renunciation is recognized by your state

The United Nations has several conventions and multilateral treaties concerning stateless persons; see http://www.unhchr.ch/ for more details.

In computer science, it is often applied to communication protocols which lack provisions (by accident or by design) for remembering, in part or in full, the message sequence that has taken place among the communicating parties: HTTP and NFS are examples of stateless protocols.

State"less, a.

Without state or pomp.

© Webster 1913.