noun
prisoner
PRIZ-ner/ˈprɪznər/
A person held in confinement without consent.
The prisoner sits on a bench behind the cell bars.

Etymology
Latin prensio meant “a taking,” which developed into captivity and then a place of confinement. The person-ending identifies someone subjected to that restraint, rather than someone who performs the taking.
In context
but now the prisoner is in fact in custody
More examples
- Several prisoners were released.
- The guards escorted the prisoner to the hearing.
- The story follows a prisoner seeking freedom.
Forms
prisoner · prisoners
imprison verb — Put someone in confinement.
Similar words
- captive
- Someone held by another's power, not necessarily in a prison.
- detainee
- Someone held in official custody, sometimes temporarily.