The term "major tranquillizer" refers to a class of drugs that are used to treat mental illnesses such as schizophrenia and bipolar disorder. These drugs are also known as antipsychotics or neuroleptics. However, there are many other synonyms to describe these types of drugs, such as anti-anxiety medications, mood stabilizers, or psychotropic medications. Some other terms include anticonvulsants, atypical antipsychotics, and first-generation antipsychotics. All these drugs work to reduce the symptoms associated with various mental illnesses by altering the chemical processes that occur in the brain. It is important to remember that these medications should only be used under the guidance of a qualified healthcare professional.