1Originally: a full release or exemption from something due, especially from a debt. Now: specifically the full discharge of a person from bankrupt status.
2The unconditional discharge of a prisoner or person charged with an offence; specifically a judicial sentence stipulating that a defendant who has been found guilty be spared punishment.
Typically in cases involving a minor offence where the court feels that punishment is inadvisable.
3The unconditional discharge of a patient from treatment for mental illness. Now: specifically (British) the discharge from compulsory medical supervision of a patient previously confined to hospital under the Mental Health Act 1983.
Late 16th century; earliest use found in John Higgins (b. c1544), poet and linguist. From absolute + discharge.