1. to perform a surgical operation on the brain (especially the prefrontal cortex) to treat severe mental illness or behavioral disorders
Usage: medical/historical; chiefly British spelling (American: lobotomize); now largely obsolete due to ethical concerns and development of psychiatric medications
2. to make someone unable to think clearly or act independently; to reduce someone's mental capacity or will
Usage: figurative; informal

Examples

• In the mid-20th century, some psychiatrists performed lobotomies to treat severe depression and schizophrenia.
• The procedure was intended to lobotomise patients with intractable mental illness, though outcomes were often tragic.
• Critics argued that the practice would lobotomise vulnerable patients without their informed consent.
• The film depicted how the experimental treatment threatened to lobotomise the protagonist's personality.
• Modern medicine has largely abandoned the practice of attempting to lobotomise patients, favoring pharmaceutical interventions instead.