1. Perform a lobotomy
   "In the mid-20th century, doctors would sometimes lobotomize patients with severe mental illnesses";
   - lobotomise [Brit]
    
2. Reduce someone's level of mental functioning
   "The constant propaganda seemed to lobotomize the population, dulling their critical thinking skills";
   - lobotomise [Brit]

Derived forms: lobotomized, lobotomizes, lobotomizing

Encyclopedia: Lobotomize