[ceejayoz]

There's usually a work component, though.

An imprisoned person may or may not be enslaved as part of that imprisonment. If they get paid a reasonable wage, they're a prisoner with a job. If they're not forced to work, they're a prisoner but not a slave.

[Aloisius]

Slavery was a condition, usually a legal status, where someone's autonomy was stripped from them.

The work component only existed because why else would one want a slave?

If someone born into slavery died before they could walk, they still were a slave. If an old slave was allowed to retire without working again, that didn't stop them from being a slave.